Also referred to as Liquid Silicone Rubber (LSR), silicone is a class of polymers made up of repeating units of siloxane.It’s rubbery and soft to touch, which has made it a manufacturers’ favorite for many years. Moreover, it’s heat resistant which opens your world to new possibilities. For instance, unlike TPE sex dolls, you can sterilize silicone by boiling, making them easier to clean and maintain.