These are not made of solid glass. The inside of the glass is actually a different piece of glass than the exterior. There is air in between the two layers. Most glasses are solid. I doubt these could withstand a week slam on the table after taking a shot. I'd prefer plastic to these. Craftsman makes other shot glasses that are solid glass but they are not shaped like sockets. Those would be the better choice.
I bought this set on a (way after) Christmas clearance sale. The shot glasses are neat and I really like the mini bar mat that comes with it.
I'm glad I got the set, but will be very careful with the glasses. With "Craftsman" on the side I would have thought they would feel tougher.