The N1178TWSHK-ST from Nascom is a recessed 1" stubby terminal switch for steel / wood doors with shark magnet, white. N1178T 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 N1178T 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 N1178T SHK Series is designed for installation in every type of hinged door including wood doors.