Pico, Medio and Gordo are our water, resistant extra durable range of Arundel seat bags. We make use of sonic welded seams and nylon fabric impregnated with thermoplastic polyurethane. Think frogman raft. The straps are also nylon and wider than usual, like seat belts in planes and cars. A wider strap means more Velcro area for better security. The materials we used cost more but in exchange, you have a seat bag that should last a good long time. All three are slightly roomier than our time proven corresponding sized Uno, Dual and Tubi. Medio 33 cubic in, 5 X 3 ¾ X 2 in Sonic welded seams Wide 1 ½ in nylon strap with extra Velcro Fits an MTB tube or two 700c gravel tubes, plus gas, filler etc.