The N505AUTMC-STFB from Nascom is a 3" overhead door rail mount open loop magnet/switch set featuring No Dead Spot technology, silver. The N505AUTM 3" TRACK MOUNT FLIP SWITCH with universal magnet handles commercial and industrial overhead door applications. The TRACK MOUNT FLIP SWITCH combines the installer's choice of contact configuration with an N35 grade NdFeB magnet for maximum gap performance. The closed-loop versions of the N505AUTMC prevent false alarms caused by the up-and-down movement of overhead doors with our unique NO DEAD SPOT technology. The switch can be mounted with the cable in either direction, without loss of gap.