Core BOTTOM is the bottom part of M5Core like M5Basic and M5 GRAY, with M-BUS socket and extend pins on the side, also include a Lipo battery . If you want to buy these bottoms separately, you can get it from here.
Bought this to add expansion options to M5Go and M5Fire.
There is no such pallet in the fire version. Therefore, additionally bought for experiments.
Bought from m5fire for the convenience of connecting third-party modules.
The base is similar the GREY Core base unit