Kayak Skeg Fin Kit Keel Replacement Intex Challenger K2 & Explorer K2 Inflatable Made from "High-Density Poly Vinyl Chloride Plastic", a very tough material This material is slightly more buoyant than water, so if it comes out, "it floats" The material is bright white, so it can be spotted from a distance The material is thicker than that of the original, allowing it to "shoulder up" on both sides of the groove on the kayak. This gives it a "tight fit" resulting in a much lower chance of it coming out. I think these enhancements greatly improve the skeg design, making it less likely to come out; and if it does it is much easier to find and retrieve as it floats.