Duralex 18-Piece Tumbler Set

purchased five of these from costco for about $12/set as had some of similar design that were about 50yrs old or so.
These have rims that get skinny and flare outward and chip like crazy - cut ourselves several times before trashing them all.

I’ve got a set from 20year old set from Williams Sonoma and added from Costco. Not sure which is which. Very durable. Mine are tempered. Didn’t check the specs. They have randomly broken though . still would recommed.