Eight day cuckoo clocks
All "8-day" Cuckoo Clocks are fitted with a mechanical movement that only requires winding every 8 days.
At the full hour, a small door opens and reveals a small cuckoo bird, which calls the number of hours (for example at 5 o'clock you will hear 5 cuckoo calls). The cuckoo bird also calls once on the half-hour.
The visible difference between 1-Day to 8-Day clocks are mostly the size of the weights with the 8-Day clocks having a noticeably larger and heavier weight than the 1-day clocks.