Colonial equivalent to C-4 explosive.
Like C-4, G-4 is a type of plastic explosive that uses a detonator as an electronic ignition source.
Sharon Valerii's Cylon persona planted five G-4 charges in the water tanks aboard Battlestar Galactica, which resulted in the loss of over 60% of the ship's water reserves.
On Galactica, G-4 explosives are located in small arms lockers, thus under the domain of the Master-at-Arms, who was Sergeant Hadrian at the time (Water).
G-4 is also used by the human resistance movements against the Cylons (Downloaded, Occupation).