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Low weight and a slim profile for keeping devices charged.
Flextail says:
At a featherweight 3 oz (85g)
We slashed volume by 44% compared to standard power banks—smaller footprint, same reliable 5000mAh capacity. Hold it in your palm and feel the difference: no more bulky bricks dragging down your pack or pocket. Light enough to forget it's there, strong enough to keep you charged.
Our Verdict
At just 84g and 7.1mm thick, the Flextail Zero Power 5K is easy to carry in a hipbelt pocket, running vest or small electronics pouch. Its flat shape avoids the bulk of thicker power banks while still providing 5,000mAh of nominal capacity.
The USB-C port supports 20W input, allowing the power bank to recharge in around two hours. Output is limited to 5V/1.6A, or roughly 8W, so it will charge a modern smartphone more slowly than many larger power banks. That matters less for smaller devices such as a GPS watch, smartwatch, headtorch or satellite communicator. For a phone, it is better suited to charging overnight rather than delivering a rapid boost during a short café stop.
The carbon-fibre shell and reinforced nylon frame provide a reassuring level of protection for such a thin unit. A large button and clear LED indicators also make checking the remaining charge straightforward. It uses the classic four-bar charge indicator rather than showing the remaining power as a precise percentage. It is simple and easy to read, although it gives you less certainty when planning how much power is left for the rest of a trip.
Great for day walks when you might need a little extra juice, as well as overnight camping trips when you don't need to keep all of your electronics topped up.
- Reviewed by Ultralight Outdoor Gear
Features
- Thinner Than Your Phone Case - Just 0.28 in (7.1 mm) thick—thinner than your phone case. Slides into any pocket, vest, or harness without a bulge. Clip it, stash it, forget it. 5000mAh power that disappears on the move
- What can Zero Power fully charge? - When your device is full, Zero Power auto-stops charging—so no energy is wasted while you sleep.
- Ultra-Light, Zero Burden - A tough, durable hanging loop clips securely to packs, harnesses, or belts. Chamfered edges and a large, glove-friendly button make it easy to check power or activate even with thick mitts. Clear LED indicators glow bright against the textured carbon shell.
- Carbon Tough, Zero Bulk - Engineered with a carbon fiber exoskeleton for rugged durability in a razor-thin profile. Whether scrambling up granite, skinning up backcountry lines, or charging through alpine storms, it tucks seamlessly into climbing gear, ski layers, or trail vests.
- Stronger Than the Trail - Zero Power is built with forged carbon fiber—a premium material used in supercars and spacecraft, now brought to trail gear. Unlike aluminum, forged carbon is compression-molded from short fiber bundles, delivering exceptional strength at ultra-low weight.
- Everyday Toughness Built In - A tough, durable hanging loop clips securely to packs, harnesses, or belts，Chamfered edges and a large, glove-friendly button make it easy to check power or activate even with thick mitts.Clear LED indicators glow bright against the textured carbon shell.
- Charge Safer With Flame-Resistant Design - Zero Power's frame is made from aerospace-grade nylon reinforced with fiberglass and an added flame retardant. It resists ignition when exposed to open flame—offering extra safety and protection for every outdoor adventure.
- Chip-Driven Efficiency - Our proprietary AI cooling tech drops surface temperature by 50% versus conventional power banks—holding steady at 35°C (95°F) while others hit 45°C (113°F). Lower heat means longer battery lifespan, safer carry in tight pockets or gloves, and reliable power in demanding conditions. Lab-proven, trail-tested—charge confidently without the burn.
- 10% More Juice, 2-Hour Turnaround - 10% more usable capacity than standard 5000mAh power banks, 20W input charging and you get a full 0–100% recharge in just 2 hours. Back on the trail, ski slope, or crag faster
- Power That Fits Your Day - From morning coffee-and-laptop sessions to lazy park afternoons, the FLEXTAIL ZERO POWER 5000C slips into any bag or pocket without adding bulk. Charge your phone or earbuds on the go—whether you're typing emails on the couch, reading under the sun, or stretching between sets. Slim, tough, and always ready for whatever your day throws at you.
- Choose Your Range - Pick the power that matches your mission. The 5000mAh ZPB 5000C delivers a full day of reliable charging at just 3 oz (85g) and 0.28 in thick—perfect for fast-and-light trail runs or single-day epics.
Need more endurance? Step up to the 10000mAh ZPB 10000C for 2-day adventures, still ultra-slim at 0.39 in and only 5.1 oz.
Specifications
- Weight: 84g
- Dimensions: 100*67.5*7.1mm (3.94*2.66*0.28inches)
- Input: 20W
- Output: 5V=1.6A
- Battery Capability: 5,000mAh(18.5Wh)
- Rated capacity: 3232mAh
- Ports: USB-C
Material & Construction
- carbon fibre
- aerospace-grade nylon reinforced with fiberglass frame
