during the first use, the key is broken at the sockets of the fastening square during disassembly of a wheel. a little disappointed I send an email to Cartec company that markets this product to get broken in this guarantee. and here I have benoit m Durafour of this company that meets me, "If you forced as a bourin, the guarantee does not work" and adds: "In any case the guarantee does not work the full moon, when trying even soaking the key in the times it works lemon juice "made to the .hormis fun of me and sell poor quality tools. I would say that one thing to avoid this company and its products. anyway you have the choice of finding largely on amazon as well and thus to work for companies that do not make fun of his clients. here is the info