High capacity 4.0Ah battery pack with no memory effect 50% longer run time as compared to Ni-Cad with minimal self-discharge Non-hazardous chemistry and environmentally safe Lightweight battery pack with impact resistant housing Performance is minimally affected by extreme temperatures The BP-84 4.0Ah Lithium-Ion Battery uses state-of-the-art circuitry to monitor and control the battery for optimal performance. LED display provides remaining battery life in 20% increments. Redesigned housing has integrated cell supports as well as conformal coating on the circuit board to protect against corrosion caused from damp environments.