I bought two gb 40s when Amazon ran a discount on them. When they arrived one was good the other wouldn't hold a charge. I contacted Noco, they said send it back. They gave me a return code and I shipped it.. Well somewhere about Memphis or got lost. Memphis said they received it but it never got scanned as having left according to the tracking number. I contacted Noco, they said there was nothing they could do. Even though I used there return and there shipper. So I got screwed out of the thing. Nico can pound sand as far as I'm concerned. I bought one of those Gooloo. I think it's better anyway.