The 714-100A uses our dual sensing VSR (710-100A-DS). A welcome addition to the 701 selector switch, it ensures you will always have a fully charged reserve battery. When the switch is in position 1 it becomes the sensing battery for the VSR. Battery 2, which is in isolation, will be charged via the VSR when the engine is running ensuring it is always fully charged. When the switch is in battery 2 position this becomes the sensing battery and battery 1 is charged via the VSR. The fact that there is always a fully charged battery in reserve is a huge safety factor.