This replacement battery from Hähnel has a 6% higher capacity than the original batery Nikon EN EL-18D
Capacity: 10.8V / 3500mAh/ 37.8Wh
Replaces Nikon EN-EL18D
Compatible with Z9 / D4 / D4S / D5 / D6
Now fully compatible with in camera charging in Z9
Compatible with MH-33 charger
Due to it’s higher capacity of 3500mAh, HL-EL18d can only partial charge with old original charger MH-25/25a (which has a build in max timer) similar to original EN-EL18d.