MOUNTAINTOP 55L/80L Hiking Backpack with Rain Cover Aluminum Rod Backpacking System- support the pack and distribute the weight of its contents across the body more appropriately, by transferring much of the weight to the hips and legs Weight adjustment Straps- Additional shoulder strap can adjust weight while hiking. Air Diversion Structure-Air circulation back pad design promote air circulation along your back and shoulders Breathable Sponge padding- Sponge padding in Shoulder, waist and back Adjustable waist belt-Adjust easily and quickly while backpacking