The mackwell advanze 2 st516 is a 5 pole isolating relay emergency inverter for use with t5 high output and circular high efficiency tubes between 22 and 55w it has a 3 hour duration and should be used with a 6 cell battery pack these inverters have several features including switch mode power supply for thermal overload protection and cathode heating ensures safe and reliable starting of t5 lamps in a variety of conditions and uses