Backpacks are bags that possess two shoulder straps which allow the wearer to carry the bag on their back. Backpacks are often associated as a student's must have school accessory for carrying books, etc from class to class.
About Ballistic Nylon:
Ballistic Nylon is a strong synthetic fabric made of woven nylon. Originally developed and used in bulletproof vests, Ballistic Nylon is now commonly employed in clothing and footwear that requires added tear and abrasion resistance.