Check the listing for details. Garage Door Roll-up Security Overhead Alarm DSC Contact Switch. Condition: New. Listed at 14.00 USD. 1 Overhead Mounted Wand or Tube Switch.The magnet is on the top left side of the photo, the reed or switch is the long pole at the bottom of the photo. On the pole there is are 2 nuts, this tightens onto either side of the plate seen at the right of the photo. (although in the white background photo the plate is in position the nuts are not in the right position and should be on either side of the plate.) The magnet goes on the roll up door and needs to be mounted within an 1/2 inch of the pole or tube. The Tube should be mounted high on the roll up door rail, some will remove one of the rail screws and mount it on the rail at the top of the roll up door. This can be used on any door though.I have shown an alternating method of mounting on the top of a door, (white magnet on L bracket) and Chrome Switch on the WALL with white CCTV clips, but the cable holds or clips are NOT included. (white) You can take out one bolt on the C rail and attach the bracket that will hold the Switch. It does not have to be flat as shown it can be at an angle, this is why the elongated hole. It does have to be within half an inch of the magnet.When the magnet is next to the switch,the loop is closed.When the magnet is pulled away the loop opens.It features:1/4" Press Fit Mini Switch18" long wire LeadsContact Rating: 10W/VASwitching Voltage (Max.) : 200 VDCSwitching Current (Max.) : 0.5 Amp.Contact Resistance (Min.) : 150 milli ohmsLife Expectancy: 10x 10 6 OperationsInsulation Resistance: 10 9 ohmsShock Resistance: 30G for 11mSec.Vibration Resistance: 20G (10 to 1000Hz)Magnets: Rare EarthPlastic Material: ABS PlasticIf you have any questions please Message BEFORE you buyThank you for doing business with usAlarm Dealers Welcome