Nitecore WDB20 is made with 500D TPU Composite Fabrics, it's IPX5 rated to withstand heavy rain, snow, and more. With the Easy-access roll-top compresses to accommodate various-sized loads; exterior straps can fasten down the roll-top opening or secure a board to the outside of the bag. YKK zippers and UTX Duraflex buckles are the best in the industry and will last you a long, long time. Modular panel for compatible packs, pouches, holsters, and more. Organize the way you like.