The N1175UM400W-ST from Nascom is a recessed 3/8" ultra mini press fit switch with D0.400" donut / magnet and wire leads, white. The N1175 UM 400 Series is an ultra-mini 3/8" recessed contact, designed to protect all nonferrous (e.g. wood, aluminum and vinyl) doors and windows, in both residential and commercial settings. The N1175 UM 400, our shortest 3/8" press fit, is the installer's choice of contact configuration where drill depth is critical and excellent air and side-to-side gaps are required to prevent false alarms caused by shifting or warping doors and windows.