They are supplied in a pack of 6. I opened 1, washed and it broke on first use. I like to use them to mix cocktails. I had a small amount of bourbon, sweet vermouth, and bitters. As soon as I put ice in the glass, I heard crackling. The crack was also visible. They must withstand the temperature shock of ice added to alcohol at room temperature. Also, they had a problem with printing. The numbers and graduations on the glass are brownish, not as bright white as they should be.