Metronomes can be bought in musical instrument stores or online. Generally speaking, there is no obvious difference between the quality of metronomes, but some metronomes are poor in workmanship and the metal materials used are easy to rust. So we'd better choose a metronome with good quality, which will take a long time.
The metronome has a pointer with a weight on it. The weight can be adjusted. The higher the metronome goes, the slower it will be and the faster it will be. We can adjust the settings according to our own needs.
In the past, metronome was only used in music learning, but now it can be used in many places. For example, breathing exercises, jumping rhythm exercises, running rhythm exercises and so on. A metronome can be used for about 10 years from purchase to elimination.
Now in addition to the above metronome, there are electronic metronomes, but there is no need to wind them up. The previous metronome clockwork is easy to rust after a period of use and needs to be refueled regularly. No electronic metronome is needed, but the battery may need to be replaced.