... of the main products in our factory, it is made from Nitrile(NBR), HNBR ,EPDM, Silicone, Fluorine(FKM,FPM), Neoprene(CR ... outer diameter Maximal 530mm2. Color: black, white, yellow, brown, green, blue, transparent, red, natural etc.3. Hardness (Shore A) :30-904 ... time15-60 daysMore information Please feel free contact with us Blue color soft silicone o ring