A genuine OEM Mackwell B903 Ni-MH 3 Cell 3.6v 4.0Ah Sealed Rechargeable Emergency Lighting Battery With Terminal Connector and Tag. Often found in emergency lighting 3-hour backup systems when paired with an emergency lighting inverter in traditional fluorescent tubes and lamp circuits, or modern led alternatives.

Mackwell B903 Ni-MH 3 Cell Emergency Lighting Battery