where would get tools to curl wig hair?

Hello! I was hopping some one would tell me what shop is best for getting a tool to curl doll hair. I know volks had hair rollers that would do it but they seem to be out of stock. I'm trying to fix some wigs that have lost their shape.

 

thanks for the advice! I didn't know that about the skewers and that you could do it wet. this will be very helpful as I won't have to buy anything. I know the wig I want to fix is heat-resistant. thanks so much.