If you have ever had an ESC burn or battery suddenly drop voltage mid-flight then you will understand the importance of having a rock solid system powering your receiver and servos.
With instant failover protection the TURNIGY Redundant DUAL 8A UBEC system is an easy choice for anyone flying large scale aircraft.
The Dual 8A UBEC controller instantly switches to the second UBEC in case of a short, burnout, or power loss (faulty battery). The LED indicates #1 or #2 UBEC live status, over voltage (short) or low battery voltage.
The TURNIGY Redundant Dual 8A UBEC can be connected to one or two battery packs and provides redundancy in the case of an electronic, connection or battery failure. In most cases UBECs fail when an FET burns, shorting the circuit, frying your battery and cutting power to your receiver. This system prevents that by keeping the circuit open and switching source to the second UBEC and battery.

A must have for larger size aircraft!

Spec.
Input: 6.6~8.4V (2 cell Lipoly) [Two battery or two conn. to the same battery]
Output:  5.9V(+/-0.5V)
Max Load: 8A
Weight: 49g
VR Mode: Linear

Included.
Dual Redundant 8A UBEC x 2
Dual Redundant Controller x 1