... Description:The frosty cup have double walls, it is made from Acrylic (sterile &innocuous material ... after frozen it does not lead to vessel broken, so the cup is safe & non-toxic.How to use:First, ... keep the cup in the refrigerator and let upside down before being put into use, after 2-4 hours, it ... could be OK for use, and input your favor drink. It can be cooled down to or ...