It's an 8 day clock that needs a good CLA.

Basic domestic clocks used to be wound everyday but for more money, sometimes a lot more, you could get an 8 day clock to enable you to wind it up once a week. These needed a bigger and better spring. It's a bit of a challenge to make a small clock which can run eight days. The clock mentioned could be a good quality aircraft cockpit clock and these are sought after by rally enthusiasts especially if has stop/start button.