The only one that comes to mind with two receiver plugs is a Castle Pro. It has two receiver plugs because it provides 10amps of power and a servo plug can only handle 5amps so you would plug both in a separate receiver slot. If you only require 5amps then just use one plug.
If it is a Castle it should be set to 4.8 volts when you connect a 2 cell to 6 cell lipo to the red and black input wires.. To change the output to 6 volts you would need the programmer.
What size battery are you using?