The Rob Allen "L" Muzzle Eye is a stainlees steel accessory that is fixed to the muzzle of any Rob Allen Speargun to create a line guide for a reel. It is situated under the muzzle and is where you would thread your dyneema line through when you are rigging up your gun to have a reel. This means that when you shoot a fish, the line will only follow straight through the 'L" muzzle eye which you can then control your fish more so.
