What's the difference between binoculars and monoculars?

Binoculars are mainly used for close observation (traveling or watching sports meetings, etc.). )

Monoscope is mostly used for long-distance observation (for example, looking at the city on the roof or peeping into other people's privacy, which is certainly not desirable)

Observing the stars is an astronomical telescope.

Which one to send depends mainly on your friend's hobbies.

If your friend is a layman, you don't need to send it at a high price (mostly professional and luxurious, more than 1000 yuan or even 10000 yuan)

If you buy binoculars, Russian binoculars are better and the price is not expensive (they are sold online, so be careful not to buy fakes).