Charge up and keep working. Compatible with the COAST XT20R Rechargeable Penlight, the ZX325 ZITHION-X(TM) rechargeable lithium-ion battery features a built-in USB-C port for easy charging. A battery charge indicator flashes red during charge-up and shines solid green when fully charged. The overcharge/discharge protection circuits make powering up as simple and safe as possible. The battery is backed by COAST's one-year warranty against defects in materials and workmanship.