This is a back case lid for the M5Stack Core2. It likely also fits the M5Stack (not tested). It contains a concealed wall mount that can be easily attached with two nails or small screws. If required, the countersink holes for the wall mount can we widened with a countersink drill bit. Depending on any stacks you attach to the front main unit, you will need appropriate lengths of M3 countersink screws. I have added one standard stackable module (Lora 433 MHz), which itself has a unit height of 6.6 mm. I now use 20 mm (top 2) and 25 mm (bottom 2) M3 screws, which fit perfectly.