this item is all new high performance current limiting device with the ability to disconnect short circuits of up to 10ka,which is the newest model in 21st century.it has many merits of high protective grade (up to ip20),high breaking capacity,good reliability of sensitive action,covenient multi-pole assorting,long using life etc.they are mainly used for overload,and short circuit protection within the circuit of ac 50hz,230v in single pole,400v in double,three & four poles of lighting distribution system in industry & commerce.