Ronfell Silicone Rubber Ronfell's silicone rubber expertise can provide you with cost effective solutions. We have over 30 years experience in the rubber industry and are vastly experienced in new product development. We are stockists of a range of silicone rubber products including, silicone rubber gaskets, silicone rubber seals, silicone rubber sponge, military silicone rubber and high temperature silicone rubber.