The low-profile of this muzzle makes for extremely low drag through the water and the very clear sight pattern along the spear is usually reserved for open-muzzle designs. The muzzle accommodates two rubbers that are clipped into place preventing 'muzzle flip' when fired. The shape of the muzzle guides the rubber in a straight line, parallel with the barrel and spear.The muzzle is constructed of bomb-proof glass reinforced polyamide and the critical muzzle-barrel interface consists of an extra-long internal spigot with external shrouds.The muzzle hole attachment point has been shaped to accept an optional stainless steel shackle recommended when a reel has been fitted.Will fit any Rob Allen barrel made since 2005.