These are ceramic balls that are perfectly round so when you use them make sure that you cut your parchment paper liner a bit bigger for when it's time to remove them from the pie shell. They will roll around and take off on you if you don't have a good grip on them. Keep a fry pan or some other heat proof container to place them in when they come out of the oven as they stay quite hot for a while. Directions say to hand wash. The container they come in is sturdy and make a great storing container for them. I'd buy them again.