A backpack—also called knapsack, schoolbag, rucksack, pack, book sack, bookbag, haversack or backpack—is, in its simplest frameless form, a fabric sack carried on one's back and secured with two straps that go over the shoulders; but it can have an external or internal frame, and there are bodypacks.
Material:
Polyester fabric.
Safety standards:
Material test: CPSIA & Prop 65 for lead and cadmium. Phthalates (7P). AZO.