My kids have these in their book bags everyday at school.
Book Bag Insert
Book Bag Insert
STRATIS Level III+ Enhanced Backpack Insert
Rifle-rated backpack armor in stock! Premier Body Armor Level III+ STRATIS backpack armor plate size 10x16. This ultra lightweight armor stops AR-15. Perfect for any bug out bag or EDC carry system. Have the lightest level 3 body armor protection wherever you go. Made in the USA.
premierbodyarmor.com