Check the listing for details. Warehouse Steel Door L Bracket Alarm System Switch Contact Sensor. Condition: New. Listed at 17.50 USD. Warehouse Steel Door L Bracket Heavy Duty Roller Shutter Garage Door Contact Sturdy Polished Aluminum Die-cast Housing Magnet Mounted on adjustable L-Bracket Wide Operating Gap 2" min. (50mm) min. Magnet Mounted on adjustable L-Bracket 3' Long PVC Armored Cable When the magnet is next to the switch in the normal position, the loop is closed. When the magnet is pulled away the loop opens. Message with questions BEFORE you purchase. Please ask if you need something other than what is listed, we carry security systems accessories, cables and sensors. Leave positive feedback once you receive your item and are satisfied with our service. You will receive positive feedback as soon as you pay for your item. Alarm Dealers are welcome.