Includes 10 pieces of Seal Stopper Silicone Rubber, diameters range from 2.5 mm to 14 mm. Key benefits Provides reliable sealing for small openings: the set covers a wide size range so you can find a snug fit without cutting or modifying pieces. Made of silicone rubber: flexible material conforms to irregular openings for a tighter seal and easy installation/removal. Reduces leaks and contamination risk: seals bottles, glassware, and holes in aquariums or similar equipment to protect contents and maintain conditions. What it does and how it helps Seals and plugs openings to prevent spills, slow evaporation, and block dust or contaminants. Flexible diameters let you match the right stopper to the application quickly, minimizing downtime or trial-and-error. Reusable and simple to clean, making the set practical for repeated use in different tasks. Important attributes Quantity: 10 pieces per set. Size range: diameters from 2.5 mm to 14 mm, covering many small openings. Material: silicone rubber, selected for its flexibility and sealing ability. Compatibility: designed to fit bottles, various glassware, and fish tank holes as stated. Practical use scenarios Laboratory or hobby glassware: seal test tubes, reagent bottles, or flasks during storage or transport. Household bottles and containers: plug small-necked bottles to prevent spills or preserve liquids. Aquariums and tanks: plug small feed-throughs or holes to control water flow or temporarily close openings during maintenance. Simple to use: choose the diameter that matches the opening, press the silicone stopper into place, and remove when needed.