My favorite massage molds are the ones I bought from soapsaloon.com and they are made of white styrene and can be used also for CP. They make a 4 1/2 oz bar. I have a lot of molds from soapsaloon and have never had one break or crack. They are much heavier duty molds than the Milky Way molds I have bought and will last a lifetime of M&P soapmaking.