The "Moonshot VV" is a drop-in '60s style preamp plate, featuring:
 
Stacked volume and tone controls for each pickup.
Large knurled knobs with original knob spacing.
Original style non-magnetic brass control plate.
Battery fits flat below the preamp (CHECK your cavity width).
 
So what is different? Under the hood, this preamp is a sophisticated "dual filter" preamp, using active filters to electronically isolate the volume and tone controls. When you change the bridge tone, it doesn't change the neck tone, and the volume controls allow precise mixing of the pickups over the entire range. You can achieve an endless variety of subtle tones, and like all Underhill preamps it has an ultra-quiet and natural sounding signal.