Battery Tender 24 Volt Power Tender Plus Battery Charger is a portable power tender which works at 2.5 ampere, constant current recharge and maintenance charger. It is fully potted therefore vibration resistant and waterproof. A mounting flange with mounting holes allow for this unit to be mounted on or in the vehicle. 4 stage charging allows all batteries to be fully recharged after use. Short circuit and reverse polarity protected with a 72 hour safety timer.