Specifications:Designed in tapered shape with stard demension, easy to plug in pull out, creating an airtight seal in the mouth of your carboy fermenter.Well made with sturdy rubber stoppers to provide the best primary fermenter arrangements possible, ideal f labaty, household, industrial use.Smooth tapered sides designed f exceptional sealing optimal fit with a wide range of openings.Various demensions to prevent oxygen from wreaking havoc with your fermenting process.Type: Test Tube Stopper PlugsMaterial: SiliconeFeatures: Soft, Reusable, Easy to Use, DurableSize 1:Top Diameter: 13mm or 0.51" (Approx.)Bottom Diameter: 9mm or 0.35" (Approx.)Height: 27mm or 1.06" (Approx.)Size 2:Top Diameter: 15mm or 0.59" (Approx.)Bottom Diameter: 11mm or 0.43" (Approx.)Height: 29mm or 1.14" (Approx.)Size 3:Top Diameter: 17mm or 0.66" (Approx.)Bottom Diameter: 12mm or 0.47" (Approx.)Height: 32mm or 1.26" (Approx.)Size 4:Top Diameter: 19mm or 0.72"Bottom Diameter: 15mm or 0.59" (Approx.)Height: 66mm or 2.60" (Approx.)Size 5:Top Diameter: 22mm or 0.86" (Approx.)Bottom Diameter: 17mm or 0.67" (Approx.)Height: 36mm or 1.42" (Approx.)Notes:Due to the light screen setting difference, the items col may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement. Package Includes5 x Test Tube Stopper Plugs