The N1178CBSHK-ST from Nascom is a recessed 3/4" stubby switch for steel / wood doors, Shark Magnet, wire leads, brown. The N1178C SHK Series is a 3/4" recessed stubby door contact couple with the patented SHARK magnet. The set is designed for residential, commercial and industrial steel and wood door applications. The N1178C SHK is the installer's choice of contact configuration because the contact set is designed to cut installation times. Just a pinch of the springs installs the SHARK magnet permanently and the powerful rare earth magnet helps to prevent false alarms caused by shifting or warping doors. The N1178C SHK Series is designed for installation in every type of hinged door including wood doors.