It allows to use 12g CO2 capsules. Adapters are designed to work with Mancraft regulators. It can by used with regulators from other companies but they must have R 1/2" thread in their products (Paintball standard).
The standard 12g capsules - for SDIK conversion kit - give around 40-70 shots - depending on the pressure settings.
Piercing: a classic cone with hole.