The ASCO Model 277 (Islatrol IE) is a series-connected DIN or flange mounted high frequency noise filter and surge suppressor. Its ideal applications include critical industrial loads drawing up to 20 Amps of continuous current.
ASCO 500 Series Surge Protective Devices explained
500 SERIES Surge Protective Devices are designed with strict industry requirements in mind. This diverse family of products uses patented surge technology to provide survivability and exceptional performance.