IT'S ONE OF THE COOLEST M5STACK COMPATIBLE PIECES OUT THERECompatible with M5StickC and M5StickC plus 2 (and all that's in between)-extremely resistent design-combinations can be made with the available parts-wrist piece can be personalized or used as it is by sticking a bolt on the holes and using it as a lock-chassis is airtight with in built tolerances-holes are 1.5 mm for the chassis bolts while the wristband are 3.5mm (recommended scaling down if smaler bolts are being used)-0.12 to 0.24mm layer height are recommended for fdm printing-recommended use of flexible/soft filaments for the wristbands--c port is available from behind, so you can charge your m5stack device or use the other support peripherals