... ring outer diameter Maximal 530mm2. Color: black, white, yellow, brown, green, blue, transparent, red, natural etc.3. Hardness (Shore A) :30 ... etc.Rubber moulding over 2000 setsWorker 150Staff25QC5Main productso rings, gaskets,custom rubber parts.Material Nitrile(NBR), HNBR, EPDM,Silicone, Fluorocarbon, SBR ...