<b>The perfect partner for your running and cycling! </b> <br/><br/>RockRain hydration backpack is a lightweight and comfortable backpack. It is perfect for running and cycling, and the lightweight design allows the backpack to follow your pace. The padded mesh on the back provides good breathability; the hydration ports on the left and right shoulders allow you to choose your preference. Its waist and shoulders can be adjusted to suit young people, men and women of different sizes. <br/><br/><b>Lightweight and able to hold essentials! </b><br/><br/>The main material of the backpack is nylon. It is water resistant so your belongings stay dry in light rain. <br/>Built-in two storage compartments, the main compartment for hydration bladder, it covered with insulation material, with the best effect to keep the water bladder cold; the other compartment can put light clothes or towels. The deep front pocket can hold mobile phone and other small items. <br/> <br/><b>The first use of water bags: </b><br/><br/>Your order includes a 2 liter hydration bladder with a large opening that also makes cleaning easy. You need to wash the bladder before the first use and then let it dry completely before reassembling. When it is dry, it is necessary to tighten the hose at the bottom so that it can seal properly and prevent leakage. <br/><br/><b>Product Parameters: </b><br/><br/>Product Dimensions: Size approx. 16.5''*7.5''*0.5'' (H*W*D) <br/>Backpack Weight: 0.78 lb<br/>Package Includes: Backpack*1 + 2L bladder*1<br/>