F.L.F. creates a deflection of a ski during edging easily, allowing easier and quicker downhill turn with a larger angle. The more edging you do, the longer the length between two contact points, allowing a grip and stability. Also, it is easy to control the speed of skiing with a larger area of edging. （PAT. No.3837716)
PPF makes a greater ski functionality in terms of rigidity by placing a sheet made by aluminum alloy in the core. It allows higher grip, and flexibility on the top and the tail of a ski. It also permits stable skiing by preventing deflection of a ski. PPF could be placed over or under the core.
This structure is the same structure as the sandwich structure except that both sides of a top sheet are slightly lowered. This is more sophisticated structure compared to sandwich structure in sense that it is more resistant to external shocks.