The N400TB-STSD from Nascom is a N400T brown single pole double throw set. Nascom's N400T 4 inch industrial surface mount screw terminal contacts protects steel doors in commercial settings. The N400T is the installer's choice of contact configuration where extra wide air and side-to-side gap are required to prevent false alarms caused by shifting or warping doors and windows. The 400T is offer extreme flexibility for installation with four possible wire directions, including the bottom.