... .Most competitive price. 4.ROHS approved. Details about o ring color code: Materials Comply with ROHS, NBR, Silicone (VMQ), EPDM, Viton, etc ... as your request.Tolerance Strictly upon international standard, no flash.Color Black, transparent, green, red, yellow, grey, purple, pink or as ... of current molds for all kinds of o ring, AS568, JS, Metric and BS o rings are all available. o ring color code