「There is a clock that "tells the correct time exactly twice a day, without a single second of error."

That would be "a stopped analog clock."
The problem is you can never know exactly when it showed the right time.
By the way, the clock in the image above is not actually stopped.

When you turn off the lights, the luminous coating painted on the hands and bar indices glows.
Anyway, changing the subject — I recently discovered that a titanium frame from a certain brand that a customer left with me has a similar feature.

When I turned off the lights to leave,
I freaked out the moment I noticed it glowing.
By the way, I'm not sure this is the right category for this post...

That would be "a stopped analog clock."
The problem is you can never know exactly when it showed the right time.
By the way, the clock in the image above is not actually stopped.

When you turn off the lights, the luminous coating painted on the hands and bar indices glows.
Anyway, changing the subject — I recently discovered that a titanium frame from a certain brand that a customer left with me has a similar feature.

When I turned off the lights to leave,
I freaked out the moment I noticed it glowing.
By the way, I'm not sure this is the right category for this post...