This ProMaster 2,250 mAh, li-ion, rechargeable battery uses an integrated USB-C port for convenient charging. Just connect to it and wait for the battery’s on-board LED light to change from red to green. It’s that easy! A USB-C to USB-A charging cord is included for your convenience. Charging will function properly using a USB power source having a minimum charging current of just 0.5A (3.0A max). The battery is compatible with cameras using the Nikon EN-EL15c battery, including the Z8 and Zf! In addition to its own on-board charging port, the battery also works with in-camera charging as well as external chargers.So, what’s so great about a built-in charging port, you may ask? While many cameras offer in-camera charging, the unfortunate disadvantage is the lengthy amount of time the charging process ties-up your camera. By charging extra batteries externally you gain the freedom to use and enjoy your camera at the same time. An alternative to in-camera charging is to use an external charger, of course. But now you have one more thing to carry and keep track of. Where do those chargers go to just when you need them? With this ProMaster battery you don’t have to worry about those problems. Just use a common USB-C charging cord (we include one for you) and you can conveniently charge your battery outside of your camera and without the need for an additional, dedicated charger.The battery is packaged in a terrific case that doubles as a protective storage unit. The case has two internal compartments for safely storing the battery as well as the included USB-C charging cable. Alternatively, you can remove the cable and store a second battery in its place. This case ensures the battery will remain clean and its contacts will not accidentally touch any metal objects or get damaged while the battery is being stored and transported.Safety features designed into this battery include: overcharge & over discharge protection, overcurrent protection, overvoltage protection (voltage regulation) and short-circuit protection.Charging time from fully depleted to 100% is approximately 3 1/2 hours (with 0.95A minimum charging current).