This is a special clock. A team from China made it.

It is the world’s smallest chip atomic (原子的) clock. It is smaller than a finger. It is also very accurate (精确的) — it only goes wrong less than 1 second in 30,000 years.

This tiny clock can help us in many ways. It can work in small satellites up in the sky. It can also help drones (无人机) fly together in groups, or guide machines under the water.