These are real mirror glass! Unlike other seller selling thin fake mirror adhesives. There are the real deal! They are heavy and shine more than regular mirror. The adhesive in the back is no joke. Once you put it on you can't take it off. So make sure you plan out and line up your design before start. The seller is super nice and reliable. I got a few pieces chipped the edges due to shipment they send me replacement right away. I used 2 boxes of 3x3 for my large maater bathroom mirror. They look more spakle and expensive in real life than in picture. They look like those fancy mirror you purchased from homegoods.