“ What material are the breastshells made out of? ”
TheraShell backings are made of soft, flexible silicone backs and include both backings for sore and inverted nipples. The domes are made of polypropylene.
SoftShells are sold with only one type of backing, either sore or inverted. The SoftShell backings are also made of soft, flexible silicone backs, but have a more flattering contour under your clothing.