Suitable for use with entire range of HARBOUR corrosion proof fitting Completely plug & play with HARBOUR range Self-Test function provides periodic, automatic testing of the fitting Low power consumption Provides 3 hour emergency discharge duration Emergency light output dependant on fitting used Wide operating temperature range of -10°C to +40°C Note: Please be aware that when using the RHA2WEMST-PSU it is not possible to wire through the below fittings RHA10402FT-24, RHA20404FT-24, RHA28405FT-24 & RHA34406FT-24