TheRob Allen Stainless Steel Line Releaseis the small hook that sits under the handle that the mono or dyneema (shooting line) attaches to, for keeping out of the way when loading your gun. Most speargunswill come with plastic line releases and over time they tend to snap off or break at the pin.Rob Allenhas a stainless steel line release that can be easily changed and will last more than double the life span of average line releases. It will not bend or snap. Line releases are generally similar in size and the pin that attaches it to the gun is normally similar in size also. The Rob Allen Stainless Steel Line Release will fit all Rob Allen Guns and the vast majority of other brand guns.