I am a boy, so I don't suggest that you must buy a brand.
It depends on his usual preferences. If he likes cloth, there are many in the general market.
If you like perforated tape, it is best to customize it;
If you like a belt with gears, it is recommended to go to a large shopping mall or online shopping. The better brands are Seven Wolves, Goldlion and Hermes ... but the latter two are too expensive. Seven wolves are good, and it can be done within 100 yuan.