I have to agree with onehundred80 on the "spring" you have pictured. That piece of metal looks to be stainless steel with no sign of heat treatment. The guy from Poland advertises his springs are made from a super alloy....okay?!? Yet he doesn't mention anything else about what alloy is used or how they are stronger. I have a problem trusting that, but that's just me. Someone needs to step up to 7 series aluminum or go back to stainless steel so we don't get more posts like these every month. That's four EC 65mm pulleys done in the last month. They may not post about it here on the forum, but four units in a bit over a month seems like something EC should rectify.