Specially treated UV protector nylon. Blocks over 97% of sun's harmful rays. 100% WATERPROOF; protects against all natural elements. Seams are four-folded, stitched and electronically heat-sealed. Shock cord allows for snug fit on all shapes. Sewn-in elastic bungees. Comes in its own fanny pack made of 300m polyester, with adjustable straps. Not intended for trailering.