Product review (4 stars): Thin and light, but does the job.
These are really thin and light, but given that they're just sitting on my two unused burners that doesn't really matter to me. The set would work great if you wanted to cover the standard two small/two large, but I'll be keeping the two not in use as backups. So far there's been no warping, even with other burners on the stove in use, and the oven up to 450F. I would NOT recommend leaving these in place over a burner (even if it's off) that functions as your oven's heat exhaust - double check if you're not sure which it is.