M430 in my wrist. It has it's own optical HR sensor. It does not need H10 to measure HR. Polar H10 is the chest strap, it used electrodes with skin contact to measure HR.

When H10 is available and paired to M430, M430 uses H10 to get more accurate HR measurement data from the strap.

H10 works also alone with a free Polar app so you don't need the wrist monitor, although M430 has GSP and screen so it can measure also distance.