This is a JR MatchMaker Servo Setup Device.  These are very useful when operation 2+ servos on the same channel.  Setting up servos just got a whole lot easier, thanks to the MatchMaker from JR. The MatchMaker lets modelers accurately center servos, evaluate end points, and cycle servos at varying speeds, without ever having to switch on a transmitter. This is the perfect bench companion for any modeler looking to optimize servo performance and compatibility.

• Allows for the cycling of up to two separate servos at a time at variable speed rates.
• Perfect for finding erratic servo behavior in the cycling mode.
• Allows the precise digital centering of up to 2 servos at a time to help with setup on the building bench.

Specifications:
Input Voltage: 4.8 - 6.0V
Dimensions (WxLxH): 1.54 x .75 x .50 in
Weight: .32 oz