Head roller result of long research, study and exhaustive testing. Study and design that prevents jams and damage to the shot, while catalyzing the usual utilitarian and functional problems such as wounding mullet roller tires, hold the spear, jamming and deformation during expansion, etc. Bring roller suitable diameter with inox bearings where friction and minimize energy losses. Designed for easy and fast installation with only 2 small holes 6 and 7 mm. the body of the weapon. Comes with guide rope, screws and hooks. Ideal for wooden and synthetic selfmade constraction rollerguns. Negative buoyancy 85gr.