Magnetic Switch, Mount: Surface, 100V AC/DC, Contact: Normally Open. Height: 2-17/32", Width: 17/32" W, Depth: 11/16", Color: White. Edwards magnetic switches are designed to activate a variety of signaling devices. Normally open circuits close when the magnet engages. SPDT switches are for open circuit systems and/or closed circuit systems. Normally closed circuits open when the magnet engages. For accessories, see Magnetic Switch Accessories. Used for commercial, industrial, and residential burglar alarm systems. Cat. No. 63 magnetic switch is supplied complete with 66-W Insulating Spacer, 67W Terminal Cover, and mounting hardware.