Havent got to try these to see how well they work or hold up but from first appearance they seem to be cut from a cheap recycled metal, a few of the keys actually show metal flashing from cooled metal liquid. However I try and bend them with hand they seem pretty sturdy
Larger than other sets of similar that I own, these are pressed out using I guess a blunt worn out die which has left rough sharp edges a quick rub over with emery paper will sort them out...cheap quality but worth a go if your curious or on tight budget.