Muzzles are used to grip and guide the spear, as well as to direct your shooting line and hold your rubbers.When fired, the primary rubber keeps the spear in place by applying stress along a line just below the rail. The second band in the double muzzle pulls from the muzzle's bottom portion. Strength in the connection to the barrel is ensured by the internal spigot and outside skirt. Constructed with 30% glass-reinforced nylon.