O-rings Viton® the ISO abbreviation is FKM. Viton® registered trademark of DuPont Performance Elastomere. 80° Shore hardness A. Viton is resistant to chemicals and heat. Operating temperature is between -15° C. to max. +200° C. O-rings are dimensioned with „inner diameter × cord thickness“, for example: 10 × 1 mm = inner Ø 10 mm, outer Ø 12 mm, cord thickness 1 mm. Other dimensions on request.