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ISO 3601 Metric O-Rings

ISO 3601

KODA’s entire standard O-ring series strictly adheres to ISO 3601-1 Class A standards, while all metric O-rings meet ISO 3601-1 Class B quality requirements. Furthermore, KODA has established a comprehensive O-ring quality acceptance system based on ISO 3601-3 Class N, classifying and defining surface defects and specifying the maximum acceptable threshold for each defect. For high-end applications, KODA offers precision tolerances and customized inspection solutions that surpass conventional standards.

ISO 3601-1: Dimensional Tolerances

ISO 3601-1 classifies O-rings into two categories: Class A and Class B. Class A O-rings use tolerance specifications consistent with the AS568 standard, with higher precision than Class B, and more stringent tolerance control, making them suitable for high-end industrial applications and high-precision applications such as aerospace. Class B O-rings have a relatively loose tolerance range, mainly meeting the needs of general-purpose applications.

ISO 3601-3: Quality Acceptance Criteria

ISO 3601-3 was initially formulated for general‑purpose O‑rings. Through continuous revision and refinement over time, the standard now defines three defect classification grades — N, S and CS — tailored to different application scenarios.
 
Grade N
Acceptance criteria for conventional general‑purpose O‑rings.
 
Grade S
Quality specifications for high‑performance industrial and aerospace sealing applications.
 
Grade CS
Designed for special and critical sealing conditions, including select aerospace systems and demanding oxygen service applications.
This standard classifies typical surface imperfections such as flash, mold offset, parting line protrusion, back rind, over‑trimming, flow marks, incomplete fill and surface indentations.

ISO 3601 Metric O-Rings Size Chart

The ISO 3601 standard, published by the International Organization for Standardization (ISO), classifies O-rings into two categories: A and B.
Category A O-rings correspond to the current American AS 568B standard (excluding O-rings specifically for 900 series pipe fittings). Their ISO 3601-1 size designations are completely consistent with the dashed numbering of the AS 568 standard.
Category B O-rings use metric sizes that are feasible and economically suitable for manufacturing processes, and are compatible with various metric thread grooves. The first digit of their size code represents the cross-sectional group AE, and the last four digits represent the inner diameter of the O-ring, with an accuracy of up to 0.1 mm.

For a complete listing of all metric o-ring sizes, visit our Metric O-Ring Cross Reference Table.

ISO 3601 Size Chart

KODA Part #ReferenceC/S (MM)I.D.(MM)C/S (Inch)L.D.(Inch)
1.80X001.8A00181.81.80.0710.071
1.80X002A00201.820.0710.079
1.80X002.24A00221.82.240.0710.088
1.80X002.5A00251.82.50.0710.098
1.80X002.8A00281.82.80.0710.11
1.80X003.15A00321.83.150.0710.124
1.80X003.55A00361.83.550.0710.14
1.80X003.75A00381.83.750.0710.148
1.80X004A00401.840.0710.157
1.80X004.5A00451.84.50.0710.177
1.80X004.87A00491.84.870.0710.192
1.80X005A00501.850.0710.197
1.80X005.15A00521.85.150.0710.203
1.80X005.3A00531.85.30.0710.209
1.80X005.6A00561.85.60.0710.22
1.80X006A00601.860.0710.236
1.80X006.3A00631.86.30.0710.248
1.80X006.7A00671.86.70.0710.264
1.80X006.9A00691.86.90.0710.272
1.80X007.1A00711.87.10.0710.28
1.80X007.5A00751.87.50.0710.295
1.80X008A00801.880.0710.315
1.80X008.5A00851.88.50.0710.335
1.80X008.75A00881.88.750.0710.344
1.80X009A00901.890.0710.354
1.80X009.5A00951.89.50.0710.374
1.80X010A01001.8100.0710.394
1.80X010.6A01061.810.60.0710.417
1.80X011.2A01121.811.20.0710.441
1.80X011.8A01181.811.80.0710.465
1.80X012.5A01251.812.50.0710.492
1.80X013.2A01321.813.20.0710.52
1.80X014A01401.8140.0710.551
1.80X015A01501.8150.0710.591
1.80X016A01601.8160.0710.63
1.80X017A01701.8170.0710.669
1.80X018A01801.8180.0710.709
1.80X019A01901.8190.0710.748
1.80X020A02001.8200.0710.787
1.80X021.2A02121.821.20.0710.835
1.80X022.4A02241.822.40.0710.882
1.80X023.6A02361.823.60.0710.929
1.80X025A02501.8250.0710.984
1.80X025.8A02581.825.80.0711.016
1.80X026.5A02651.826.50.0711.043
1.80X028A02801.8280.0711.102
1.80X030A03001.8300.0711.181
1.80X031.5A03151.831.50.0711.24
1.80X032.5A03251.832.50.0711.28
1.80X033.5A03351.833.50.0711.319
1.80X034.5A03451.834.50.0711.358
1.80X035.5A03551.835.50.0711.398
1.80X036.5A03651.836.50.0711.437
1.80X037.5A03751.837.50.0711.476
1.80X038.7A03871.838.70.0711.524
1.80X040A04001.8400.0711.575
1.80X041.2A04121.841.20.0711.622
1.80X042.5A04251.842.50.0711.673
1.80X043.7A04371.843.70.0711.72
1.80X045A04501.8450.0711.772
1.80X047.5A04751.847.50.0711.87
1.80X050A05001.8500.0711.969
1.80X053A05301.8530.0712.087
1.80X056A05601.8560.0712.205
1.80X060A06001.8600.0712.362
1.80X063A06301.8630.0712.48
1.80X067A06701.8670.0712.638
1.80X071A07101.8710.0712.795
1.80X075A07501.8750.0712.953
1.80X080A08001.8800.0713.15
1.80X085A08501.8850.0713.346
1.80X090A09001.8900.0713.543
1.80X095A09501.8950.0713.74
1.80X100A10001.81000.0713.937
1.80X106A10601.81060.0714.173
1.80X112A11201.81120.0714.409
1.80X118A11801.81180.0714.646
1.80X125Al2501.81250.0714.921
2.65X004.5B00452.654.50.1040.177
2.65X005.3B00532.655.30.1040.209
2.65X006B00602.6560.1040.236
2.65X006.9B00692.656.90.1040.272
2.65X008B00802.6580.1040.315
2.65X009B00902.6590.1040.354
2.65X009.5B00952.659.50.1040.374
2.65X010B01002.65100.1040.394
2.65X010.6B01062.6510.60.1040.417
2.65X011.2B01122.6511.20.1040.441
2.65X011.8B01182.6511.80.1040.465
2.65X012.5B01252.6512.50.1040.492
2.65X013.2B01322.6513.20.1040.52
2.65X014B01402.65140.1040.551
2.65X015B01502.65150.1040.591
2.65X016B01602.65160.1040.63
2.65X017B01702.65170.1040.669
2.65X018B01802.65180.1040.709
2.65X019B01902.65190.1040.748
2.65X020B02002.65200.1040.787
2.65X021.2B02122.6521.20.1040.835
2.65X022.4B02242.6522.40.1040.882
2.65X023.6B02362.6523.60.1040.929
2.65X025B02502.65250.1040.984
2.65X025.8B02582.6525.80.1041.016
2.65X026.5B02652.6526.50.1041.043
2.65X028B02802.65280.1041.102
2.65X030B03002.65300.1041.181
2.65X031.5B03152.6531.50.1041.24
2.65X032.5B03252.6532.50.1041.28
2.65X033.5B03352.6533.50.1041.319
2.65X034.5B03452.6534.50.1041.358
2.65X035.5B03552.6535.50.1041.398
2.65X036.5B03652.6536.50.1041.437
2.65X037.5B03752.6537.50.1041.476
2.65X038.7B03872.6538.70.1041.524
2.65X040B04002.65400.1041.575
2.65X041.2B04122.6541.20.1041.622
2.65X042.5B04252.6542.50.1041.673
2.65X043.7B04372.6543.70.1041.72
2.65X045B04502.65450.1041.772
2.65X046.2B04622.6546.20.1041.819
2.65X047.5B04752.6547.50.1041.87
2.65X048.7B04872.6548.70.1041.917
2.65X050B05002.65500.1041.969
2.65X051.5B05152.6551.50.1042.028
2.65X053B05302.65530.1042.087
2.65X054.5B05452.6554.50.1042.146
2.65X056B05602.65560.1042.205
2.65X058B05802.65580.1042.283
2.65X060B06002.65600.1042.362
2.65X061.5B06152.6561.50.1042.421
2.65X063B06302.65630.1042.48
2.65X065B06502.65650.1042.559
2.65X067B06702.65670.1042.638
2.65X069B06902.65690.1042.717
2.65X071B07102.65710.1042.795
2.65X073B07302.65730.1042.874
2.65X075B07502.65750.1042.953
2.65X080B08002.65800.1043.15
2.65X085B08502.65850.1043.346
2.65X090B09002.65900.1043.543
2.65X095B09502.65950.1043.74
2.65X100B10002.651000.1043.937
2.65X106B10602.651060.1044.173
2.65X112B11202.651120.1044.409
2.65X118B11802.651180.1044.646
2.65X125B12502.651250.1044.921
2.65X132B13202.651320.1045.197
2.65X140B14002.651400.1045.512
2.65X150B15002.651500.1045.906
2.65X160B16002.651600.1046.299
2.65X170B17002.651700.1046.693
2.65X180B18002.651800.1047.087
2.65X190B19002.651900.1047.48
2.65X200B20002.652000.1047.874
2.65X212B21202.652120.1048.346
2.65X224B22402.652240.1048.819
2.65X230B23002.652300.1049.055
2.65X236B23602.652360.1049.291
2.65X243B24302.652430.1049.567
2.65X250B25002.652500.1049.843
3.55X014C01403.55140.140.551
3.55X015C01503.55150.140.591
3.55X016C01603.55160.140.63
3.55X017C01703.55170.140.669
3.55X018C01803.55180.140.709
3.55X019C01903.55190.140.748
3.55X040C04003.55400.141.575
3.55X041.2C04123.5541.20.141.622
3.55X042.5C04253.5542.50.141.673
3.55X043.7C04373.5543.70.141.72
3.55X045C04503.55450.141.772
3.55X046.2C04623.5546.20.141.819
3.55X047.5C04753.5547.50.141.87
3.55X048.7C04873.5548.70.141.917
3.55X060C06003.55600.142.362
3.55X061.5C06153.5561.50.142.421
3.55X063C06303.55630.142.48
3.55X065C06503.55650.142.559
3.55X067C06703.55670.142.638
3.55X069C06903.55690.142.717
3.55X071C07103.55710.142.795
3.55X073C07303.55730.142.874
3.55X075C07503.55750.142.953
3.55X077.5C07753.5577.50.143.051
3.55X080C08003.55800.143.15
3.55X082.5C08253.5582.50.143.248
3.55X085C08503.55850.143.346
3.55X087.5C08753.5587.50.143.445
3.55X090C09003.55900.143.543
3.55X092.5C09253.5592.50.143.642
3.55X095C09503.55950.143.74
3.55X097.5C09753.5597.50.143.839
3.55X100C10003.551000.143.937
3.55X103C10303.551030.144.055
3.55X106C10603.551060.144.173
3.55X109C10903.551090.144.291
3.55X112C11203.551120.144.409
3.55X115C11503.551150.144.528
3.55X118C11803.551180.144.646
3.55X122C12203.551220.144.803
3.55X125C12503.551250.144.921
3.55X128C12803.551280.145.039
3.55X132C13203.551320.145.197
3.55X136C13603.551360.145.354
3.55X140C14003.551400.145.512
3.55X145C14503.551450.145.709
3.55X150C15003.551500.145.906
3.55X155C15503.551550.146.102
3.55X160C16003.551600.146.299
3.55X165C16503.551650.146.496
3.55X170C17003.551700.146.693
3.55X175C17503.551750.146.89
3.55X180C18003.551800.147.087
3.55X185C18503.551850.147.283
3.55X190C19003.551900.147.48
3.55X195C19503.551950.147.677
3.55X200C20003.552000.147.874
3.55X212C21203.552120.148.346
3.55X218C21803.552180.148.583
3.55X224C22403.552240.148.819
3.55X230C23003.552300.149.055
3.55X236C23603.552360.149.291
3.55X250C25003.552500.149.843
3.55X258C25803.552580.1410.157
3.55X265C26503.552650.1410.433
3.55X280C28003.552800.1411.024
3.55X290C29003.552900.1411.417
3.55X300C30003.553000.1411.811
3.55X307C30703.553070.1412.087
3.55X315C31503.553150.1412.402
3.55X335C33503.553350.1413.189
3.55X355C35503.553550.1413.976
3.55X020CO2003.55200.140.787
3.55X021.2CO2123.5521.20.140.835
3.55X022.4CO2243.5522.40.140.882
3.55X023.6CO2363.5523.60.140.929
3.55X025CO2503.55250.140.984
3.55X025.8CO2583.5525.80.141.016
3.55X026.5CO2653.5526.50.141.043
3.55X028CO2803.55280.141.102
3.55X030CO3003.55300.141.181
3.55X031.5CO3153.5531.50.141.24
3.55X032.5CO3253.5532.50.141.28
3.55X033.5CO3353.5533.50.141.319
3.55X034.5CO3453.5534.50.141.358
3.55X035.5CO3553.5535.50.141.398
3.55X036.5CO3653.5536.50.141.437
3.55X037.5CO3753.5537.50.141.476
3.55X038.7CO3873.5538.70.141.524
3.55X050CO5003.55500.141.969
3.55X051.5CO5153.5551.50.142.028
3.55X053CO5303.55530.142.087
3.55X054.5CO5453.5554.50.142.146
3.55X056CO5603.55560.142.205
3.55X058CO5803.55580.142.283
5.30X037.5D03755.337.50.2091.476
3.55X038.7CO3873.5538.70.141.524
3.55X050CO5003.55500.141.969
3.55X051.5CO5153.5551.50.142.028
3.55X053CO5303.55530.142.087
3.55X054.5CO5453.5554.50.142.146
3.55X056CO5603.55560.142.205
3.55X058CO5803.55580.142.283
5.30X037.5D03755.337.50.2091.476
5.30X038.7D03875.338.70.2091.524
5.30X040D04005.3400.2091.575
5.30X041.2D04125.341.20.2091.622
5.30X042.5D04255.342.50.2091.673
5.30X043.7D04375.343.70.2091.72
5.30X045D04505.3450.2091.772
5.30X046.2D04625.346.20.2091.819
5.30X047.5D04755.347.50.2091.87
5.30X048.7D04875.348.70.2091.917
5.30X050D05005.3500.2091.969
5.30X051.5D05155.351.50.2092.028
5.30X053D05305.3530.2092.087
5.30X054.5D05455.354.50.2092.146
5.30X056D05605.3560.2092.205
5.30X058D05805.3580.2092.283
5.30X060D06005.3600.2092.362
5.30X061.5D06155.361.50.2092.421
5.30X063D06305.3630.2092.48
5.30X065D06505.3650.2092.559
5.30X067D06705.3670.2092.638
5.30X069D06905.3690.2092.717
5.30X071D07105.3710.2092.795
5.30X073D07305.3730.2092.874
5.30X075D07505.3750.2092.953
5.30X077.5D07755.377.50.2093.051
5.30X080D08005.3800.2093.15
5.30X082.5D08255.382.50.2093.248
5.30X085D08505.3850.2093.346
5.30X087.5D08755.387.50.2093.445
5.30X090D09005.3900.2093.543
5.30X092.5D09255.392.50.2093.642
5.30X095D09505.3950.2093.74
5.30X097.5D09755.397.50.2093.839
5.30X100D10005.31000.2093.937
5.30X103D10305.31030.2094.055
5.30X106D10605.31060.2094.173
5.30X109D10905.31090.2094.291
5.30X112D11205.31120.2094.409
5.30X115D11505.31150.2094.528
5.30X118D11805.31180.2094.646
5.30X122D12205.31220.2094.803
5.30X125D12505.31250.2094.921
5.30X128D12805.31280.2095.039
5.30X132D13205.31320.2095.197
5.30X136D13605.31360.2095.354
5.30X140D14005.31400.2095.512
5.30X145D14505.31450.2095.709
5.30X150D15005.31500.2095.906
5.30X155D15505.31550.2096.102
5.30X160D16005.31600.2096.299
5.30X165D16505.31650.2096.496
5.30X170D17005.31700.2096.693
5.30X175D17505.31750.2096.89
5.30X180D18005.31800.2097.087
5.30X185D18505.31850.2097.283
5.30X190D19005.31900.2097.48
5.30X195D19505.31950.2097.677
5.30X200D20005.32000.2097.874
7.00X109E109071090.2764.291
7.00X112E112071120.2764.409
7.00X115E115071150.2764.528
7.00X118E118071180.2764.646
7.00X122E122071220.2764.803
7.00X125E125071250.2764.921
7.00X128E128071280.2765.039
7.00X132E132071320.2765.197
7.00X136E136071360.2765.354
5.30X140D14005.31400.2095.512
5.30X145D14505.31450.2095.709
5.30X150D15005.31500.2095.906
5.30X155D15505.31550.2096.102
5.30X160D16005.31600.2096.299
5.30X165D16505.31650.2096.496
5.30X170D17005.31700.2096.693
5.30X175D17505.31750.2096.89
5.30X180D18005.31800.2097.087
5.30X185D18505.31850.2097.283
5.30X190D19005.31900.2097.48
5.30X195D19505.31950.2097.677
5.30X200D20005.32000.2097.874
7.00X109E109071090.2764.291
7.00X112E112071120.2764.409
7.00X115E115071150.2764.528
7.00X118E118071180.2764.646
7.00X122E122071220.2764.803
7.00X125E125071250.2764.921
7.00X128E128071280.2765.039
7.00X132E132071320.2765.197
7.00X136E136071360.2765.354
7.00X140E140071400.2765.512
7.00X145E145071450.2765.709
7.00X150E150071500.2765.906
7.00X155E155071550.2766.102
7.00X160E160071600.2766.299
7.00X165E165071650.2766.496
7.00X170E170071700.2766.693
7.00X175E175071750.2766.89
7.00X180E180071800.2767.087
7.00X185E185071850.2767.283
7.00X190E190071900.2767.48
7.00X195E195071950.2767.677
7.00X200E200072000.2767.874
7.00X206E206072060.2768.11
7.00X212E212072120.2768.346
7.00X218E218072180.2768.583
7.00X224E224072240.2768.819
7.00X230E230072300.2769.055
7.00X236E236072360.2769.291
7.00X243E243072430.2769.567
7.00X250E250072500.2769.843
7.00X258E258072580.27610.157
7.00X265E265072650.27610.433
7.00X272E272072720.27610.709
7.00X280E280072800.27611.024
7.00X290E290072900.27611.417
7.00X300E300073000.27611.811
7.00X307E307073070.27612.087
7.00X315E315073150.27612.402
7.00X325E325073250.27612.795
7.00X335E335073350.27613.189
7.00X345E345073450.27613.583
7.00X355E355073550.27613.976
7.00X365E365073650.27614.37
7.00X375E375073750.27614.764
7.00X387E387073870.27615.236
7.00X400E400074000.27615.748
7.00X412E412074120.27616.22
7.00X425E425074250.27616.732
7.00X437E437074370.27617.205
7.00X450E450074500.27617.717
7.00X462E462074620.27618.189
7.00X475E475074750.27618.701
7.00X487E487074870.27619.173
7.00X500E500075000.27619.685
7.00X515E515075150.27620.276
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