Power that Outlasts the Night, Not Your Batteries

Meet the Fenix ARB-L21-4000P, the rechargeable 21700 battery that actually keeps up when your headlamp is begging for mercy. If your trail runs on high output and questionable decisions, this is the sidekick you want in your kit. AXG Life? You’re Life, Adventure-Ready—with extra juice.

Key Features & Design

• Form factor: 21700 lithium-ion battery with a substantial 4000 mAh capacity.
• Discharge performance: up to a peak of 18 A with a continuous output of 10 A.
• Three overheat protections built in: pressure relief vents, microporous protection, and a PTC cathodal block.
• Rechargeable and ready to roll again after every adventure.
• Shipping note: lithium-ion batteries are considered dangerous goods for transport and are typically moved by ground. Orders with loose batteries can take longer than expected.

Performance / Benefits

This battery is designed for high-current lights and devices that sip power in leaps rather than sips. The ARB-L21-4000P keeps high-output modes running longer, so you don’t have to swap cells mid-mission or accept dimming as your constant companion. With robust overheating protections, you get peace of mind on trail runs that go past midnight, and you don’t have to babysit your pack every time you push the button.

In AXG terms, it turns stuck weekends into hero stories and powers midnight trail runs and questionable decisions alike. It’s built for outdoor enthusiasts who want reliable power without the drama of battery drama.

Closing CTA

Add to cart and tuck this power mule into your pack—outsmart the dark and keep your gear running Life, Adventure-Ready.