The award-winning Sea to Summit Ultra-Sil Day Pack is a minimalist backpack that has incredible strength-to-weight performance and packs down to the size of a tennis ball. The 30D siliconized CORDURA® fabric and reinforcing bar-tacks at stress points enable it to withstand loads many times its own weight. With a 20L capacity, it's just right for a summit pack, carrying groceries when on foot or on a bike, or as an extra traveling tote. The tiny packed size also easily fits onto your key ring, in a jacket pocket, or a purse. The maximum load limit recommendation for a comfortable carry is 15 lbs / 7 Kg.