The well established RL/RB system continues to be available. It comprises of the RB2 battery pack, which is fitted to the RL1 internal light, or the RL4 external light (requires 2 x RB2 batteries). The battery is connected to the lead by a polarised sealed plug. This is fixed in placed by a screwed locking ring, which enables easy service and replacement. Classified as Hazardous for Shipping Purposes – See PSDS The external light is designed to produce a minimum of 4.3cd in all directions for 12 hours. The internal light is designed to produce a minimum of 0.5cd in all directions for 12 hours. The system has a maximum shelf life of five years from date of manufacture.