Midea's half-round wrench for the pre-filter is generally available online. If you don't need it urgently, you can buy it online. It's not expensive and it's convenient to find it everywhere. But if you need it urgently, I guess you have to go to the hardware store to ask. Generally, such stores have it.

In the process of daily use of the tap to take water, it is also a flushing of the water purifier. It is recommended to open the tap and flush it after taking the purified water to flush away the trapped pollutants in time, maintain a high water flux of the water purifier, and thus extend the service life.