Anker has introduced the Nano Power Bank (5K, MagGo, Slim), a thin, magnetic battery designed to attach to the back of Qi2-compatible iPhones. Certified for Qi2 wireless charging, the battery uses the MagSafe standard and offers up to 15 W of charging power. It has a 5,000 mAh capacity, which is enough to recharge most iPhone models partially but not fully for larger devices like the iPhone 16 Pro Max. Ahead of Amazon's Prime Flash Days, the battery is currently available at a 20 percent discount, priced at 39.99 euros instead of the recommended 49.99 euros. The product is intended for users who need a convenient, discreet supplement to their phone’s battery, rather than a long-term backup. The Nano Power Bank (5K, MagGo, Slim) is designed to be unobtrusive, with a thickness of less than one centimeter and a weight of around 120 grams. This allows it to stay attached to the phone during use and easily fit into pockets or bags. Certified for Qi2, it ensures precise magnetic alignment and supports wireless charging at up to 15 W. During a test by Cult of Mac, an empty iPhone 15 Pro regained 20 percent of its charge in just over 20 minutes. The battery has a single USB-C port that can both charge the battery and power a connected device. When connected to a power source, it can also charge the phone that is attached to it. According to Cult of Mac’s measurements, the battery provides about 91 percent of a charge for an iPhone 15 Pro, 80 percent for an iPhone 16 Pro, and only 63 percent for an iPhone 16 Pro Max. Anker claims the battery stays below 40 degrees Celsius during charging, with a recorded peak of around 38 degrees Celsius. The typical user profile is someone with an iPhone 12 or newer who keeps the battery in their pocket and attaches it to the phone when the battery level drops. The battery can also charge AirPods stored in a Qi2-compatible case at 5 W. Compared to larger 10,000 mAh models, the Nano 5K prioritizes thinness over extended battery life. The Anker MagGo Power Bank 10K for Qi2-compatible iPhones is often recommended for users needing more capacity, as it doubles the battery size and supports up to 30 W on USB-C, starting at 59.99 euros. However, the Nano 5K costs 20 euros less and focuses on a compact form factor that can be carried without much thought. Its wireless charging is limited to 15 W, while newer Qi2.2 models can reach up to 25 W. The Nano 5K has several advantages, including a slim profile, magnetic Qi2 attachment, wireless charging up to 15 W, a 20 W USB-C port, the ability to charge the phone while the battery is connected, and controlled temperatures during use. However, it has some limitations, such as only providing a partial charge for iPhone Pro Max models, wireless charging restricted to 15 W without Qi2.2, a single USB-C port for all functions, and a glossy surface that can show scratches over time. The Prime Flash Days have not yet started, but Amazon already lists the Anker Nano Qi2 battery at 39.99 euros, a 20 percent discount from its recommended price of 49.99 euros. At this price, the Anker Nano 5K MagGo Slim becomes a practical supplementary battery for recent iPhone users. It doesn’t offer long-term autonomy but avoids the need to rush to an outlet at the end of the day without weighing down your pocket. The Qi2 certification and controlled temperatures recorded during tests provide reassurance for daily use. The discount, while modest, applies to an accessory used regularly. If you use a Pro Max model or need a battery for several days without access to an outlet, or if your phone runs on Android without a magnetic case, a 10,000 mAh battery would be a better choice. For an iPhone that needs to last until the evening, excluding Pro Max models, the Nano 5K covers the essentials in a form factor that is easily forgotten. The choice between thinness and autonomy remains the key trade-off in this purchase. To take advantage of Amazon's Prime Flash Days, you must first subscribe to an Amazon Prime membership. For this, it's simple: create an Amazon account and subscribe to one of the Amazon Prime offers: Amazon Prime for 69 euros per year, Amazon Prime for 6.99 euros per month, or Amazon Prime Student for 3.49 euros per month (for students and those aged 18-22). Current promotions include Cyberghost VPN for 2.19 euros per month for 2 years + 2 months free (-82 percent), the B&You 100Go 5G plan for 13.99 euros per month with no commitment, Deezer Premium offered for 3 months, cancellable at any time, the Fulli Balade toll tag badge offered for 12 months with the code RENTRE26, Avast One Premium Security antivirus for 2.57 euros per month for 1 year (-70 percent), Intego One Complete antivirus for Mac at -50 percent for 2 years, and 1minAI, lifetime access to the best AI, for less than 36 euros.