The BT-4 Combat features tournament legal external velocity adjuster, removable grip frame for quick and easy upgrades, tactical collapsible car stock, impact resistant baked on coating, dual pica tinny mounting rails, modular trigger system, slide-away feedport, adjustable vertical front grip and a barrel adapter to allow use of multiple barrel threads. The BT-4 Combat is set up to easily accept expansion chambers, vertical and horizontal bottle adapters and will work with cO2 or compressed air. The lightweight and balanced construction make it a comfortable paintball marker and it comes with a 1 year full parts and labor warranty through the manufacturer.