Model : 109 RMLamp Type : 1 X 09 W CFLAccumulator : Ni-Mh Ni-Cd Rechargeable BatteryBattery Backup : 4 Hrs Consists of single or more Fluorescent tubes which provides illumination on normal mainspower supply and the same tubes continues to provides illumination during mains failure onself contained battery source. On resumption of mains supply the tubes switch back to themains automatically and simultaneously recharge the battery to the required level.All maintained models provides uninterrupted illumination.