Ultra-Sil Shopping Bag A reusable shopping that will hold up over the years is the most earth-friendly choice you can make. The Sea to Summit Ultra-Sil Shopping Bag is made of the same high tear strength fabric we make our pack covers, compression sacks and stuff sacks of, so they’re 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 won’t fall apart like other shopping bags on the market. And because the Ultra-Sil Shopping Bag is so compact and lightweight you can stash it anywhere - the tiny packed size fits easily onto a key ring with a specially designed snap tab or tucks in a purse or in a jacket pocket, so you’re more likely to have one with you when you need it.