Using the ISO 3601 chart to spec your O-ring
ISO 3601 is the international O-ring size standard engineers reach for when a drawing calls out a metric O-ring by code rather than a raw dimension. Part 1 (ISO 3601-1) fixes the inside diameter, cross-section and dimensional tolerances — Class A sizes mirror the AS568 inch series, while Class B covers true metric sizes — and Part 3 (ISO 3601-3) defines the visual quality-acceptance grades (N, S and CS) for surface and molding defects. Read the chart to confirm the exact ID x CS, the tolerance class and the quality grade before you release the part, so the seal drops into your groove and passes inspection the first time.
Once you have the size and grade, ARC molds it to your spec. Twenty years of US custom rubber manufacturing, ISO 9001:2015 and IATF 16949:2016 certification, and a full range of compounds — NBR, HNBR, FKM/Viton, EPDM, silicone and more — mean you pick the material and hardness for your temperature, pressure and chemical duty, and we hold the ISO 3601 dimensions and quality grade you need. Send a size code, cross-section or drawing and our engineers confirm material, tolerance class and grade with a fast quote.