Lightweight, druable 210D nylon fabric. Insulated mesh back panel and ventilated mesh shoulder straps. 1 liter capacity bladder.Mini Hydration Pack with insulated mesh back panel and ventilated mesh shoulder straps is made of lightweight, durable 210 Denier nylon fabric. Features include a 1 liter capacity bladder and a front flap pocket. 7W x 12.75H x 2D. Great size for any activity.