There is a Zhong You drugstore next to Xiguan Bus Station. There is an oxygen generator in the equipment area on the second floor above. There are various kinds, such as Ying Weikang, Turtle, Yu Yue and so on. They are chain stores, which are more reliable, but the price is a bit high, but don't worry about buying such expensive things. You can go and have a look. I bought a deer and haven't found any problems yet ~ ~