Specifications: Designed in tapered shape with standard demension, easy to plug in or pull out, creating an airtight seal in the mouth of your carboy or fermenter. Well made with sturdy rubber stoppers to provide the best primary and fermenter arrangements possible, ideal for laboratory, household, and industrial use. Smooth and tapered sides designed for exceptional sealing and optimal fit with a wide range of openings. Various demensions to prevent oxygen from wreaking havoc with your fermenting 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 the light and screen setting difference, the items color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes 5 x Test Tube Stopper Plugs