Electronic Switch from GT Power - GTPELSWITCH
This simple, compact product allows you to switch on-board electronics on\/off using a spare channel on your radio transmitter. Ideal for hobbyists looking to remotely control lights, smoke systems, sounds systems, cameras, cargo doors, tow hooks, or any other on-board electronic device. 
Features:

Compact and light weight
Versatile design can be used to control virtually any on-board electronic device
High quality electrical components and durable case design ensure worry-free operation for your critical components.

Specifications:

Weight: 8g
Dimension: 25mm x 10mm x 5mm
Receiver input power: 4-8.4V DC
Auxiliary input power: 0-40V DC
Output continuous current capacity: 7A
Output peak current capacity: 10A

Note: No PDF is available at this time for the manual.  Here is an image showing the back of the package for reference.