The Lite-Plan HRN/T5/4/21+22 Module is a 3hr emergency lighting module. Specifically designed for use with 21w & 22w T5 Circular fluorescent lamps.4-pole change over relay plus additional 5th pole for HF ballast isolation. This Lite-Plan conversion kit has the following benefits :- Specific T5 lamp calibration to maximise BLF%, 4 pole changeover relay, additional 5th pole relay, Deep discharge protection, Low profile enclosure, constant current charger and high temperature NiCd cells.