It has an adjustable shoulder strap design, which can be used as a chest bag,shoulder bag or messenger bag according to your needs and mood.The wide shoulder strap is flexible and comfortable to wear.The special feature of this sling backpack is that the strap can be switched from left to right.When you carry heavy objects for a long time,the backpack will make your shoulders sore.But with this shoulder bag, you can change to another shoulder to relax.