DIN 3771 is a German standard for O-ring sizes, issued by the German Institute for Standards (Deutsches Institut für Normung). This standard identifies O-ring sizes by their inner diameter and cross-section (ID x C/S), and may include a letter indicating the quality level (N for normal quality, S for special quality) along with a code for the rubber material and hardness. DIN 3771 is widely used in German and European machinery, automotive, and industrial equipment where metric sizing is required.
ZSR Silicone manufactures silicone O-rings that fully match DIN 3771 standard sizes. If your equipment follows German or European design specifications and requires metric O-rings with defined quality grades, we can supply the correct DIN 3771 size in the silicone material that matches your application needs.
Simple DIN 3771 O-rings Size Chart
DIN 3771 Standard No. Range | CS (mm) | ID Range (mm) | OD Range (mm) | CS (inch) | ID Range (inch) | OD Range (inch) |
|---|---|---|---|---|---|---|
1.8 X 1.8 ~ 17 X 1.8 | 1.80 | 1.80 ~ 17.00 | 5.40 ~ 20.60 | 0.071 | 0.071 ~ 0.669 | 0.213 ~ 0.811 |
14 X 2.65 ~ 38.7 X 2.65 | 2.65 | 14.00 ~ 38.70 | 19.30 ~ 44.00 | 0.104 | 0.551 ~ 1.524 | 0.760 ~ 1.732 |
18 X 3.55 ~ 200 X 3.55 | 3.55 | 18.00 ~ 200.00 | 25.10 ~ 207.10 | 0.140 | 0.709 ~ 7.874 | 0.988 ~ 8.154 |
40 X 5.3 ~ 400 X 5.3 | 5.30 | 40.00 ~ 400.00 | 50.60 ~ 410.60 | 0.209 | 1.575 ~ 15.748 | 1.992 ~ 16.165 |
206 X 7 ~ 670 X 7 | 7.00 | 206.00 ~ 670.00 | 220.00 ~ 684.00 | 0.276 | 8.110 ~ 26.378 | 8.661 ~ 26.929 |