It takes all 3 machinegun slots to make sure you cant have a machinegun and a septic spray and other tanks can't hold them. The septic spray is a hose that attaches to the turret of an APC. When shot, it shoots a special liquid that is designed to slow down infantry and reduce their stamina by constricting their breath, therefore making them easy to keep by your team or for you to runover. If shot at tanks, it will catch in the treads and make them move slower. Optional: partially blinds infantry.