The battery for Canon's R5 and R6 are of a higher capacity than the batteries used for DSLR cameras such as the 5D and 7D-series, because these two mirrorless cameras use more battery power. I should purchase an backup battery for my R6, but so far I haven't had the need for a second battery because of the following: the batteries I use with the 5D and 7D DSLR cameras are fully compatible with the battery in the R6. So I can always remove the battery from one of these two cameras and use it as a backup, but at a reduced capacity. All these batteries are similar, except that the one in the R6 is of a higher capacity.