TPR/TPE - Thermoplastic Rubber/Elastomer is a synthetic mixture of rubber/plastic and elastomer. While TPR/TPE is hypoallergenic in nature it cannot be boiled. Use soap and warm water or toy cleaner to disinfect.
Silicone - Silicone is a synthetic compound best known for its ability to retain heat. Silicone is non porous which makes it hypoallergenic and easy to clean and sterilize by boiling or putting it in the dishwasher. Silicone has no detectable odor.