There have been many threads on the Viper website....general discussion is it is NOT worth the money for the Optimas, they sometimes quit holding the charge, etc....My general feeling is buy a Sears Gold with a 3 year warranty etc, for about 1/3 the price, they immediately replace the battery if anything goes wrong....a lot of the trucks are sitting a lot of the time, another good thing IF yours sits a lot is install a simple battery disconnect on the negative terminal and this will also save the battery from being run down, I don't care whatever you pay for one !!!