A Lego Technic Balance Clock with Korfhage differential powered remontoire.
Dimensions : 34cm (W) x 29cm (H) x 15cm (D)
You will need 6 AA batteries for running the clock. The clock operated the remontoire each 5min and the accuracy is about 1-5min for 24h after fine tuning.
You can see more picture and review of this machine and sample of the instructions here : https://www.nico71.fr/balance-clock-with-remontoire/
The package includes genuine Lego parts and PDF building instructions.
The clock is not very complex to set up, especially if you have already did complex building, please follow carefully this video : https://www.youtube.com/watch?v=ZUq02ubd5v8
Then, note the building is composed of many moving axle and gears in the drivetrain. Please pay attention to not stress the gearing, axles and bushes, and bracing correctly each, in order to have free rotation on every axle to avoid problem of functioning and bad autonomy or reliability.