It's a hydraption pack,which can use for outdoor sports,like running,cycling,hiking,camping,climbing and daily training. 1.The fabric is nylon ripstop with PU coating and light waterproof function.The fabric color is very bright,suitable for both male and female. 2.Size is W20cm*H41cm 3.reflective screen printing and reflective band on the front part for visibility and safety. 4.front pocket with #5 zipper for keys, phone, snacks etc, 5.external expandable stash zone with 4pcs durable buckles for towel,helmet,clothes etc 6.main pockets with #5 double-way zipper,you can put 1.0~2.0L bladder by velcro adjusted straps. 7.two side fabric pockets for alpenstock and climbing accessories. 8.mesh shoulder padding and back for breathable 9.two sides can be used suitable for both left and right handers 10.special zipper puller 11.D ring on both shoulder straps for carabiner 12.chest straps with buckles can be adjusted to make confortable 13.wrist straps with buckles can stop shaking 14.inside silk binding to be strong 15.handle straps for easy carry this is a multifunctional style for outdoor sports