The Fenix ARB-L21-6000B Rechargeable Powerbank Battery offers a high-capacity 6000mAh energy reserve within a compact 21700 battery format. It supports efficient USB-C charging and not only powers your 21700 battery flashlights but can also serve as a power source for other USB-C devices using only the included USB type C cable. THIS BATTERY IS NOT AN 18650, AND IT IS NOT COMPATIBLE WITH 18650 FLASHLIGHTS. Recommended for use only in these Fenix products purchased in 2025 or later. Compatible products: HT18R, HT18RV2.0, HT32, TK16 V2.0, TK17, TK20R V2.0, TK21R, TK22R, TK30R, WF25RM, CL27R, LD35R, LD36R, LD45R, LR35R-Pro, LR36R, LR50R, PD45R-ACE, PD40RV3.0, PD36RV2.0, PD36R-Pro, PD36R-ACE, E35R, CP50R. Not compatible with older Fenix models that utilize a 21700 battery such as the Version 1 of the PD36R. COMPATIBLE CHARGERS ARE THE ARE-A2, ARE-A4, ARE-D1, OR ARE-D2. Will not work in older chargers such as the ARE-C1 and other "C Series" chargers. 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 common.