1x Alarm kit Auto-Dialer (ebay $10-$20)
1x Door/Window Sensor (included in alarm kit)
1x Keypad/Control Unit with AC Adaptor (included in alarm kit)
1x Telephone Cable (included in alarm kit)
2x Cable Ties (home depot or Lowes)
A simple way to set up an alert system, after installed, you still have the option on turning on or off the system, when mailbox door is open this system will phone you automatically, Completely Wireless, sensors have a 200 feet range and 400 feet line-of-sight range.