What is this?The Rubber Tapered Plug is great for laboratory utensils such as flasks, test tubes, or other laboratory applications, also can as a sewer plug, water pipe plug, or drain plug.What will I get?The tapered plug is in size of: Bottom Diameter: 48mm / 1.89 inch; Top Diameter: 56mm / 2.2 inch; Height: 25mm / 0.98 inch; In the package of: 5 x Rubber Tapered PlugAre there any advantages of the product?Made of Rubber, with good resistance to chemicals, acid and alkali resistance, can withstand high temperatures in a short time.How to use it?Conical design, solid, easy to install and good sealing performance, flexible and durable, not easy to crack, shrink, harden or break.