The Ultra-Sil NanoShopping Bag is constructed using lightweight 15 denier siliconized nylon. Its generous 25L capacity is reinforced by bar-tacks so it easily supports loads in excess of 45 lbs / 20kg-a lot more than you'll comfortably carry over your shoulder! This tiny reusable shopping bag is amazingly strong and durable. We've also made sure that the stress points have bar-tacked reinforced stitching. You can fill these shopping bags to capacity week in, week out and they will keep performing like new.