SECO-LARM SM-226RQ ENFORCER Overhead Door-Mount Magnetic Contact, Closed Loop, Adjustable to Fit Most Door-channel Widths, 2-3/4" (70mm) Gap, 24" (61cm) Wire Leads Enclosed in Armored Cable Used for overhead doors in both industrial and residential situations where a wide gap is present Switch contained in curved low-profile cast-aluminum housing for surface mounting on garage floor Magnet enclosed in epoxy compound inside aluminum case for direct installation to garage door with no projecting bracket to break or serve as a handle 24" (61cm) wire leads enclosed in armored cable Contact reed switch is SPST, deactivated rhodium on gold under-plating, for a long life