Like a pit-bull the Swat is compact and vicious. The first BT marker to offer the new Magazine expansion chamber as a standard feature. The Magazine expansion chamber not only gives an authentic military look and feel, it also improves the efficiency of your CO2 air source by letting the liquid CO2 expand into a gas rather than potentially pushing liquid co2 through your BT-4. With the magazine expansion chamber, looks are certainly more than skin deep.