The Fenix ARB-L18-3500 is a high-capacity 18650 rechargeable Li-ion battery, offering 3,500 mAh within a standard size that fits most high-performance flashlights. Built for safety and durability, it includes a button-top design, integrated protection circuitry against overcharge, over-discharge, short-circuit, and overheating, plus pressure relief vents to prevent buildup and reduce risk of swelling or rupture. A robust steel-infused anode structure further improves impact resistance and electrical safety. This cell is rated for up to 500 charge cycles, maintaining around 75% capacity afterward, and carries Fenix’s 12-month warranty. Key Specifications: Capacity & Voltage: 3,500 mAh, 3.6 V Protection Features: Overcharge, over-discharge, short-circuit, overheat protection; pressure relief vents; reinforced steel anode Design: Button-top, compatible with Fenix and other 18650 devices Durability: Up to 500 charge cycles, retains ~75% capacity over time Size & Weight: Approx. 69 mm length × 18.6 mm diameter; ~50 g Warranty: 12-month manufacturer’s warranty A reliable, long-lasting, and safe power solution—perfect for tactical flashlights, headlamps, lanterns, and high-drain devices. Note: This item is packaged and priced as one battery. Shipping Note: Lithium ion batteries are considered "dangerous goods" per US transportation regulations and can often only be transported via ground shipment. Orders containing loose batteries will typically take much longer than predicted to be delivered. Delivery times of 14+ days are not uncommon.