Stilson Vacuum Cup Elastomer Section: All materials except chloroprene are specially formulated to be non-marking. If cups will be exposed to oils or chemicals, select the most compatible material. Silicone-ET for extremely cold or hot environments. Use flourocarbon (Viton) for high temperature applications in automotive, appliance, or other plants where Silicone is forbidden. Chloroprene is the rubber industry name for ordinary neoprene rubber. Viton is a registered trade name of the E.I. DuPont Company.