This is a Bright Source Emergency 4 Cell Battery Stick 4.8v 4.0ah, a D cell nickel-cadmium rechargeable battery with flying leads, ideal for use within emergency lighting applications. This battery is equivalent to the Yuasa 4DH4-0L4. These batteries are often used with emergency bulkheads, polo fittings and with LED panels and downlights for emergency uses. Typically used in offices, corridors, exit areas, schools and public buildings. Please note that Ni-Cd batteries are supplied with a residual charge and should be charged at the continuous charge rate before use.