Training or mag-fed paintball play goes extremely well with the 8-Shot Quick Pierce magazine in your T4E Walther PDP marker. Load up the magazine with the ammo of your choice and pre-stage a 12 gram non-threaded CO2 cartridge and store away in a magazine pouch for use when you need it. To activate the Quick Change magazine, simply swat the knob on the bottom with your palm and the CO2 will be instantly activated.