Designed to work in coordination with the Push Button Buttstock Guide and Gas Through ASA by Killhouse Weapon Systems, the 13ci/5oz Buttstock Black allows a user to run either a 13/3000psi air tank or a 5oz CO2 tank inside the stock itself. Gone are the days of carrying your air tank on your back or sacrificing comfort while your tank hangs off the bottom of our gun. With the 13ci/5oz Buttstock Black by Killhouse Weapon Systems you can eliminate the need for remote coils and hit the field with a low profile kit, that is the closest thing to a real steel feel possible in paintball!