The Degradable Mailing Bags is made of PLA, which is kind of degradable material. These Degradable Shipping Bags are white outer surface, black inner lining, so it looks like light grey color not a true bright white. The Poly Mailers used of opaque materials convenient for protect your privacy with a professional appearance. the edge seal adopts advanced heat sealing technology, explosion-proof edge, the raw material adopts anti-static treatment, and the opening is good. 16 17/32" L x 11 1/32 W