The F20 is a heavy duty roller shutter contact, sealed against outside attack by a hard wearing resin.
18″ (457mm) of fly lead is provided, encased in a steel armoured sleeve. The sleeve itself is capped with a grommet for ease of installation to junction boxes etc.
Contact dimensions are 150x40x15mm and the magnet is 60x75x32mm overall. This contact operates at a gap of approximately 50mm.