sentences:  The gunner's station is provided with a single 12.7mm Browning M2 heavy machine gun, which could be mounted in a fully enclosed turret or simply on an open ring mount.Various models were proposed which replaced the heavy machine gun mounting with twin general-purpose machine guns, a 20 mm autocannon, a 60 mm gun-mortar, or a bank for launching anti-tank guided missiles.Both crew members have access to roof hatches over their respective seating positions.