This is the Rob Allen Aluminum Snapper Railgun Speargun with Open Muzzle Features: Aircraft grade aluminum Vecta, the strongest, smoothest and most robust mechanism available Railguns are unique in the sense that they have an extended rail" incorporated into the aluminum barrel for the full length of the shaft This rail supports the spear the full length of the barrel and continues on into the muzzle The rail barrel tube is also much stiffer and stronger than a normal tube because it is thicker-walled and has a slightly bigger diameter The integrated rail adds further strength. Rob Allen also uses aircraft grade aluminum when the barrels are extruded This gives the barrel even better strength and stiffness, enabling it to handle strong rubbers and be used in longer lengths without flexing It is essentially stronger and stiffer than wood of the same diameter Includes 7mm shaft The Rob Allen Railgun is the ultimate in speargun technology, offering a powerful, fast, well balanced rig with the added bonus of being streamlined enough to appeal to those who prefer to hunt their fish at greater depth or in adverse conditions. "