The Ledlenser Flex5 is a compact, rugged power bank built around a single replaceable 21700 lithium-ion cell, which is included. Ledlenser describes it as a six-in-one tool: it works as a power bank to top up a phone or other USB device, as a charger for the 21700 cell with a charge level indicator, as safe storage for a spare battery, as a display to check the remaining capacity, and it has double protection against short circuits. The cell can be swapped quickly, so you can carry a charged spare for a Ledlenser torch or headlamp that uses the same 21700 battery and recharge it in the Flex5 later. The housing is made of PC and ABS, is water resistant to IP65 and measures about 120 x 54 x 29 mm. Weight with the battery is around 126 g. The supplied cell is rated 3.7 V and 4500 mAh, and a full charge takes about 140 minutes.