Due to the extreme angles the Hummer is subjected to, the battery acid can leak causing electrical and safety problems. Yellow Top Deep Cycle batteries by Optima are made from a cell that can be mounted in any angle even punctured with no battery acid leaks. The yellow top gives improved cranking power and durability over the stock battery. The deep cycle will allow you to completely drain the battery over and over without damaging the cell�s. Great for winching!