What is the difference between 12g cartridges, bulk fill, and 88g AirSource?

A 12-gram cartridge (Powerlet) is the most common single-use cartridge and yields roughly 30 to 60 useful shots in a typical pistol or rifle.

Bulk fill systems use a refillable tank or paintball-style bottle to feed liquid CO2 into a larger onboard reservoir for hundreds of shots before refill. Crosman's 88-gram AirSource and similar 90-gram cartridges are large single-use cartridges used on certain rifles for many more shots than a 12g without paintball-tank infrastructure.