Are you looking for a practical stopper for your experiment? Do you want a reliable test tube plug? If your answer is yes, please come and take at this product. This test tube stopper is made of good material, which has the . It will meet your experiment sealing needs. Features -Color:Black -Material:Rubber -Size:4.10X4.10X2.50cm/1.61X1.61X0.98in -Size:3.70X3.70X2.50cm/1.45X1.45X0.98in -Size:3.20X3.20X2.50cm/1.26X1.26X0.98in -Size:2.70X2.70X2.50cm/1.06X1.06X0.98in -Size:2.60X2.60X2.50cm/1.02X1.02X0.98in -Size:2.50X2.40X2.40cm/0.98X0.94X0.94in -Size:2.50X2.00X2.00cm/0.98X0.79X0.79in -Size:2.50X1.90X1.90cm/0.98X0.75X0.75in -Size:2.50X1.70X1.70cm/0.98X0.67X0.67in -Size:2.50X1.50X1.50cm/0.98X0.59X0.59in -Note:comes with 11 different sizes. -Suitable for test tubes, flasks and other laboratory equipment that need to be sealed. -Widely applied in laboratories, research institutes, universities and other places. -The rubber stoppers are small in size and light in weight, convenient to store and use. -There are enough bottle stoppers to meet your different needs. You can use it with confidence. -Fine workmanship rubber material, and good durability, can be used for a long time. Package list: 5 x 000# Stoppers 2 x 00# Stoppers 2 x 0# Stoppers 2 x 1# Stoppers 2 # Stoppers 2 x 3# Stoppers 2 x 4# Stoppers 1 x 5# Stoppers 1 x 6# Stoppers 1 x 7# Stoppers 1 # Stoppers