The Rob Allen Spear Barb or flopper is the small barb the sits just back from the tip of a spearthat opens after have been shot. It is designed to hold the fish in place until you get to the spear and take it off yourself. Without a flopper of Spear tip, the fish could potentially slide off if it was to put up a fit after being shot. The Rob Allen 71mm barb fits 7mm and 7.5mm spears and comes with the pin to attach it to the spear. Made from stainless steel, this is string and durable.