Paintball Drop forwards help balance your gun by allow the tank to mount forward and down. Most guns use an inline bolt pattern at the bottom of the trigger frame. Some spyder guns have an offset or staggered pattern. Many drop forwards will accomodate variations in bolt patterns. If you are buying a drop forward for a sypder or clone it may be a good idea to purchase a bottomline adapter block. This allows you to convert an offset pattern to an inline pattern. This make your gun a universal fit to the majority of drops on the market. Tippmann A-5 owners will have to purchase an A-5 grip adapter. The stock tank adapter mounts in a unique way on the A-5. The adapter acts as a mounting surface to bolt most of the drop forwards to the Tippmann A-5. Other paintball drops feature an on/off system that allow you to degass your system without disconnectin your tank.