Genuine Echo replacement part. Genuine Echo Replacement Part. New, Bulk Packed. Consult owners manual for proper part number identification and proper installation. Please refer to list for compatibility. The ECHO 58-Volt 4.0Ah Lithium-Ion Accessory Battery Pack features triple protection electronics to prevent overcharging, overheating and overloading. With a 1-hour recharge time, users can complete big jobs without worrying about running out of power. 4.0 Amp hour lithium-ion battery 1 hour recharge time Triple protection electronics prevent overcharging, overheating, and overloading Integrated fuel gauge Superior cold weather performance Compatible with all ECHO 58-Volt lithium-ion tools and chargers