The Snap-n-Charge is small as power banks go, and only 3,200 mAh/16 Wh. This is good enough for a quick top-up of a smartphone or headphones. And a top-up is what you get -- the capacity is enough for about a 50% top-up for a smartphone or portable speaker, or about three or four recharges of earbuds or headphones. The power bank is housed in a polymer shell that shrugs off impacts and damage from being rattled around pockets and bags with things like keys.