Snap Disc

These concave bi-metallic thermostats discs are heat sensitive and will deform and make a clicking noise when the temperature rises.
Overheating or many years of use will raise the temperature threshold when the disc makes a clicking noise.

Tempest click discs have a hole in the middle to let space for the Visual Indicator screw and Pointer.

To replace the click discs, the VI coil/spring and the VI Pointer has to be disassembled, it can be a hard task for some people to install these parts correctly.
Click discs concave shape go in this way: Screw head, [_ )(__VI pointer & coil, Induction sleeve and Cap, Bowl.

The two click discs are accurate for the first heating from room temp, but after that, there is only one click disc that can be used for a reheating/next bowl.
A magnet helps to click back the fast one within 30 sec. The longer one will click back, like a few minutes later.

With the Wand IH, first click is at ~20sec when the VI pointer is at the first notch, second click is at ~30sec when the VI pointer is at the second notch.
Stopping the heating at the second click is great for a lower temp heat cycle.
Wand timer heat cycles usually go beyond the second click, up to 20sec after for a high temp cycle.

I personally use the Wand temp heat cycles or the Visual Indicator feedback far more often than the click discs.
For a timeline perspective, my unit is from the Tempest first release, August 2024.
Improvements could be already done for the click discs depending on when you read this.

Please, don't heat the VI housing directly and watch out for possible dust/particles/anything, who could enter inside the Visual Indicator housing and make the VI not function properly.
Heating directly (torch or IH) the VI housing will damage your temp indicators forever.

Also, keep in mind when cleaning, that the VI spring and the click discs are more subjects to flash rusting.
Dry them with a slow Tempest heat cycle, and don't let them in a high humidity air environment for long-term storage.
For long-term storage, I use a Vitamin C effervescent tablet plastic tube, with some desiccant salt inside the lid, to store all my Tempest small spare parts.