Universal wheel Suitable for Mi Air purifier Pro and MAX, non-destructive installation. Why spent hundreds of dollars on buying an air purifier but have troubles? Inconvenient to move, it is difficult to clean at the corners You need a well-designed universal wheel Tailored made and well designed It moves smoothly, does not fall off, and has a high degree of Fit nicely, the air purifier can move flexibly without falling off the wheel. Lightweight and flexible, silent and durable Simple installation, push button to lock, close fitting with air purifier