Just bought and installed one this very night. I have the Optima Red Top 75/35 size battery and it fits great. To my surprise, I made sure the guy didn't forget to give me the height adapter, only to discover later that I didn't really need it. I also picked up some of those toolless terminals that have a quick-release lever - they're a nice little bit of convenience so you can connect/disconnect it in a flash with no need to get the right sized tool. I'm not a member at Costco and let my Sam's membership expire, but did alright - Pep Boys here didn't have one in stock and Sears wanted $129.99, so I went and paid $108.99 at the Advance Discount Auto Parts here.