A Clean Booth is a movable structure with a HEPA Filter on its top and vinyl curtain covered around. Its design is simple but it is a vertical laminar clean room, providing a high level of cleanliness up to Class 100. The air passes through the HEPA Filter, comes inside the booth and goes out through the bottom. In that case, a small amount of positive pressure is maintained inside, preventing any external air from coming in, so it can keep a high cleanliness level.