FS260-Pro means high quality cycling clothing & accessories. Endura's performance arm warmers give you wind stopping protection where it counts, without having to wear a heavy jacket. Combining Thermolite & Entrant fabrics makes the FS260 Pro arm warmers great windstoppers as well as attaining a balance between waterproofing & breathability. In effect this means these are not totally waterproof, but do withstand the average shower or lighter rain, & the benefits of being highly breathable & windproof are invaluable. Recently reviewed in Cycling Plus Magazine, who called them " Top quality armwarmers that don't ride down while you're riding."