Nylon brooks rain cover protects your leather saddle from moisture if a wet saddle is ridden not only the colour may stain your clothing but the leather top may easily deform the nylon rain cover is an improved version of the tradiitonal rain cover building on feedback provided by the brooks community available in 2 sizes regular all road mtb touring trekking b67 b72 b18 large b73 b190 b135 b33