Do you think this pocket is a key, a change or a lighter? All wrong! The correct answer is the pocket watch

The jeans invented in the 19th century were specially sold to the miners’ work clothes. At that time, the workers could only use the pocket watch to see the time.
But in order not to let the pocket watch collide and scratch at work, this small pocket was specially designed. Now the pocket watch has already entered history, and the small pocket is still a classic element of jeans.