C-7 Foaming Explosive

"We used to call him Foamy. explosives specialist, used to always carry a can of C-7. Used to hide with guys deodorant or shaving foam in the barracks. We thought it was funny as fuck, until Kanna. Foamy leaps from the trench, ducks under the firing arc of the Wraith gunner, climbs behind it and pumped an entire can of C-7 into the reactor. After seeing the size of that fireball, we double checked out cans from then on."

- Corporal Jack Whistler

is a UNSC explosive device designed for demolitions. C-7 exists as a liquid when contained inside a pressurised vacuum, but once it contacts with oxygen it turns into a semi-solid explosive.

Uses
Composition-7 foaming Explosive is often used for more delicate operations, such as breaching, using the explosive to cut through a wall or door, opening hardened equipment with minute, controlled explosive or controlled ordnance detonation. However, in enough amounts, the explosive can be used for serious destruction, allowing it to be injected into cracks inside structures or armour or rigged up as crude time bombs.

Operation
The C-7 is contained inside a sealed titanium allow can, with an folding nozzle. This allows it to be accurately inserted. Its got a screw lock pressure cap, allowing the flow of the C-7 to be modified by the operator.