SIZE: 3.5 x 2.3 INCH Optimize the battery, extend battery ... 8-10 years, or repair used battery. SIZE: 3.5 x 2.3 INCHFeatures:1. Optimize the battery, extend battery ... voltage, thus protect the vehicle's electrical or electronic appliances;5. No need to plug in to the power source, ... applicable to vehicles, but also to all appliances using lead acid battery, like UPS power supply, boat, yacht, solar lamp, ...