A double roller setup can effectively be used as "two spearguns in one". Using a quickly removable knot, a hunter can easily remove one of the bands and use the speargun as a single roller. This is helpful when encountering poor visibility, or hunting in rocks and reef. When conditions require longer range, the band can be added and the speargun used as a double roller. 

The double roller muzzle for spearguns is made of fiberglass-reinforced nylon. With larger wheels on the front, it allows the bands to lay and function with less interference during the shot. It features a bridge to secure elastics after firing and can accommodate up to 15mm bands. It’s suitable for tubes with diameters from 26 to 26.7mm. 

• Bridge on top of muzzle stops wishbones and ensures and no interference with the accuracy of the shot. 

• The overlapping system is made possible by two different pulley sizes: a front pulley with a diameter of 36 mm and a rear pulley of 28 mm. This system provides smoother and more efficient operation. 

• The muzzle can accommodate elastics up to 15 mm wide, providing sufficient power for various shaft diameters.

• It is designed to be suitable for tubes with diameters ranging from 26 to 26.7 mm, offering versatility for use with different types of spearguns.

• Ceramic bearings can be added.

• The front of the muzzle can accept a threaded shark spike.