Common Sense RC Lectron Pro 6.6V 2000mAh 5C LiFe Receiver Hump Pack with Servo C

6.6V suggests you will not require a regulator!
This 6.6V (2-cell) 2000mAh 5C LiFe (lithium iron phosphate, LiFePO4) receiver battery provides a great combination of efficiency and convenience. Our LiFe batteries have some unique advantages over other battery alternatives that make them ideal for use in radio systems:

Voltage stays above 5V throughout your whole run, so you get more constant servo speed and torque than with NiMH batteries

A little lower voltage than Lipos suggests you can securely link 6.6V (2-cell) LiFe batteries to your receiver without needing a voltage regulator
Our 2000mAh capacity beats the 1300-1800mAh you'll find in basic flat and hump packs from most other suppliers

Specs
Port: JR (Universal) Servo Port

Dimensions:
Length: 56mm (2.20 in.)
Width: 32mm (1.26 in.)
Height: 28mm (1.10 in.)
Weight: 91g (3.21 oz)