With this Extention you can control a Servo, which does mechanically unlock / lock a door. The Interlock can be controlled on the WiFi Homepage, if all your mysteries have been solved.  The moving direction, the start and end positons can be adjusted in the Admin Area of the SmartGeocache, so it will perfectly fit mechanically to your Geocache door. The Servo has metal gears which are very robust and strong. You can combine this Extention with other Extentions:

WiFi Laser Station, WiFi LED Station, WiFi UV Station.

Specifications:
Dimensions: 23 x 12.2 x 29mm
Operating Speed (4.8V no load): 0.11sec / 60 degrees
Operating Speed (6.0V no load): 0.10sec / 60 degrees
Stall Torque (4.8V): 2.2 kg/cm
Stall Torque (6.0V): 2.5 kg/cm
Temperature Range: - 30 to + 60 °C
Dead Band Width: 10us
Operation Voltage: 4.8 - 6.0 Volts