The Sea to Summit Ultra-Sil Shopping Bag is a small, reusable bag made of the same strong fabric they make our pack covers, compression sacks, and stuff sacks from, so it's amazingly robust and durable. The stress points also have bar-tacked reinforced stitching so it can be filled week in, and week out and still perform like new. And because the Ultra-Sil Shopping Bag is so compact and lightweight, you can stash it anywhere - it clips easily onto a key ring with the attached carabiner or tuck into a purse or a jacket pocket, so it's never out of reach.