The NPW235 Rechargeable Lithium-Ion Battery is a spare or replacement item for the one originally included with the camera. The battery is compatible with the dedicated Twin Battery Charger or can be charged in-camera.
You can increase charging efficiency by purchasing the FUJIFILM BC-W235 Dual Battery Charger enabling you to charge two NPW235 batteries at the same time.
NOTE: AC Power Adapter (AC-5VJ, provided with X-T4) and USB cable (Type-C, provided with X-T4) are required to charge batteries with BC-W235.