HK Army 20oz Aluminum CO2 Tank Marker Upgrades These two things combined make

These two things combined make for dramatically improved firing characteristics and shot grouping that you can see and feel with every shot

those are all great must have features

Factory Replacement parts for the Tippmann M4 airsoft gun

Gearbox Material: Cast Zinc Alloy

HK Army 20oz Aluminum CO2 Tank Marker Upgrades These two things combined makeThis HK Army 20 ounce CO2 tanks will allow to play almost all day without having to refill. You can through 1000 shots without having to refill. Aluminum construction means that the tank is lightweight, even once filled. *Tank will ship empty in order to comply with shipping regulations. Tanks purchased in store will come with the first fill for free!