The Nikon EN-MH2-B4/MH-73 is a kit containing 4 EN-MH2-B4 rechargeable NiMH batteries and the MH-73 charger. Nickel-metal hydride batteries not only reduces the burden on the environment, but further increases the practicality of the COOLPIX L100 by increasing the number of shots that can be taken with a set of fully charged batteries.The Battery Charger MH-73 allows for simultaneous charging of sets of four batteries.