The electronically controlled impulse switches ISS and ISS U1 can be used without any issues in environments where conventional electromechanical impulse relays are considered disturbingly loud, thanks to their very quiet switching behavior. The flush-mounted version ISS U1 is also suitable for easily retrofitting existing systems or for renovation of older buildings, and due to its compact dimensions, it can be installed in switch or junction boxes. Relay contacts normally open, potential-free, 16A 250V AC, dimensions: 18x55mm, 230VAC 1S pf 16A ISS 1.