silicone o ring,nonstandard o ring,un-standard o ring,unstandard rubber o ring silicone o ring,nonstandard o ring,un-standard o ring,unstandard rubber o ring1. Material: Silicone, NR, NBR, EPDM, SBR, Nitrile, Viton, BUAN, CR, IIR ... and so on.2. Size: According to your ...