Specifications: Designed in a tapered shape with standard dimensions, easy to plug in or pull out, creating an airtight seal in the mouth of your carboy or fermenter. Well made with sturdy silicone stoppers to provide reliable performance for primary and secondary fermentation, ideal for laboratory, household, and industrial use. Smooth and tapered sides designed for exceptional sealing and optimal fit with a wide range of openings. Available in multiple sizes to help prevent oxygen exposure during the fermentation process. Type: Test Tube Stopper Plugs Material: Silicone Features: Soft, Reusable, Easy to Use, Durable Size 1: Top Diameter: 13mm / 0.51" (Approx.) Bottom Diameter: 9mm / 0.35" (Approx.) Height: 27mm / 1.06" (Approx.) Size 2: Top Diameter: 15mm / 0.59" (Approx.) Bottom Diameter: 11mm / 0.43" (Approx.) Height: 29mm / 1.14" (Approx.) Size 3: Top Diameter: 17mm / 0.66" (Approx.) Bottom Diameter: 12mm / 0.47" (Approx.) Height: 32mm / 1.26" (Approx.) Size 4: Top Diameter: 19mm / 0.72" Bottom Diameter: 15mm / 0.59" (Approx.) Height: 66mm / 2.60" (Approx.) Size 5: Top Diameter: 22mm / 0.86" (Approx.) Bottom Diameter: 17mm / 0.67" (Approx.) Height: 36mm / 1.42" (Approx.) Notes: Due to differences in lighting and screen settings, the actual item color may vary slightly from the images. Please allow slight variations in dimensions due to manual measurement. Package Includes: 5 x Test Tube Stopper Plugs