The shoulder belts are adjustable according to the stature of different people.To position the backpack over your head while climbing up the slope, it is more labour saving.To position the back pack in the same level of your head while walking on ground to lower the center of gravity.TheThe shoulder belts are adjustable according to the stature of different people.To position the backpack over your head while climbing up the slope, it is more labour saving.To position the back pack in the same level of your head while walking on ground to lower the center of gravity.The bottom compartment is for holding sports shoes and other outfits.The straps of both sides top and bottom are used for bringing map, umbrella and mats, water bottle, keys, ice, axe etc.The top compartment is for loading torch and other tools for hiking.The expandable strap on both sides can enlarge the volume of the bag.There are aluminum that stays in backside, so your back will get scientific-protection in different bearing conditions.