5000 mah power bank. Very small and compact: 2 1/2" X 2" weight: 3.5 oz. Great for backpackers and day campers. Tested and it charged my phone twice and a re-chargeable flashlight and still had 3 bars lit out of 4. I carry 2 of these devices on overnight backpacking trips. This item retails for each on the Chargeball website.