The first pan warped, and became unusable due to it not being flat on the stovetop (we don't have a gas stove). We returned it to Calphalon, and they sent a replacement. The replacement warped while we were heating it, before we even got the food into it. Very disappointed, and we weren't using high heat. We're not going to spend another $12 to ship it back for yet another replacement. This pan was part of a set, and the smaller fry pans have been fine. I don't recommend the Tri-Ply Stainless 12 inch fry pan. Glad to see others are not having the problem, but it is rather perplexing. I really wanted this pan to be great!