The Belkin BoostCharge external battery is available in two versions: one with a 10,000 mAh capacity and another with double that at 20,000 mAh. This article focuses on the smaller, more compact 10,000 mAh model, which is also the more affordable option. During the French Days on Boulanger, a popular retail event in France, the price of this model has been significantly reduced. With an additional 30% refund from the brand, it can be purchased for 11.83 euros—well below its standard price of 21.99 euros. The Belkin BoostCharge includes a USB-C cable, which is convenient for users who might forget to bring their own. It supports a fast 20 W charge, which is suitable for modern smartphones. The battery is compact and lightweight, measuring 9.9 x 6.4 x 2.3 cm and weighing just 220 grams. It also features a second USB-C port, enabling users to charge two devices at the same time. However, the 20 W charging power is shared between the two ports, and the 10,000 mAh capacity is enough to charge a smartphone more than once but not a laptop. One notable feature of the Belkin BoostCharge is the pass-through function, which allows users to charge their device while the battery itself is being charged. However, if both ports are used at the same time, the power is divided, and neither port receives the full 20 W. The charging status is indicated by a simple LED light that changes color to show whether the battery is charging or fully charged. The Belkin BoostCharge is considered a practical and reliable external battery, though it is not a device that most people use daily. It is particularly useful in situations like long parties or days with heavy smartphone usage. The French Days 2026 event, which is returning for its second special edition, is ongoing until September 14th and offers a range of tech deals. Some of the best offers during this period can be found at Fnac/Darty, Boulanger, and Cdiscount, among other retailers.