Abstract: A dental mirror structure contains a body and a connector. The body includes an inspector, a connection segment, and a first air conduit. The inspector includes a lens, and the first air conduit has an inlet and an outlet adjacent to the lens. The connector is hollow and columnar, and the connector includes a second air conduit defined on a center thereof, a connection portion extending from a first end of the connector, a first stem extending from the connection portion, a second stem extending from a second end of the connector, and a fixing extension extending from the second end of the connector and surrounding the second stem. Thereby, the first stem is connected with an air supply element, the second stem is fitted with the inlet the body, and the fixing extension is connected with the connection segment.

Abstract: An air-filtering device has an outer plug, an inner plug, a nose clip, and a filter. The outer plug has a contacting portion and flip lid pivotally connected to the contacting portion. The contacting portion has a first receiving space. The flip lid has a second receiving space. The inner plug is mounted in the outer plug and has a third receiving space communicating with the first receiving space and the second receiving space. The nose clip is connected to the flip lid to connect the outer plug securely with the nose clip. The filter is mounted in the third receiving space of the inner plug.

Abstract: The present invention provides a cup lid including a top shield, at least two ring shields, and at least two snap-on components. The ring shields extending from a lower edge of the top shield downward are peripherally spaced from each other. Each snap-on component extends from the lower edge of the top shield downward and is arranged between two adjacent ring shields. Each snap-on component includes a U-shaped border, a tab, and at least one Y-shaped resisting member. The U-shaped border and the top shield define an opening. The tab extends from the U-shaped border outward. The Y-shaped resisting member extends from an interior of the U-shaped border upward and is bendably held in the opening. The cup lid can be fitted on a cup body or separated from the cup body through the Y-shaped resisting members without a further operation step for repeated utilization and environmental effect.