@deryaa1214 This is a simple level gauge; when placed on a surface, the position of the bubble in the center indicates the surface's levelness. If the bubble is centered, the surface is level; if it leans to the left or right, the surface is not level.
@Fa21519230 For the past few years, I have been working on matters related to this; I can tell you all with full responsibility that no one has developed effective antibodies from the vaccine—it is a massive scam!