Laboratory rubber stopper
A laboratory rubber stopper or a rubber bung is mainly used in chemical laboratory in combination with flasks and test tube and also for fermentation in winery.
Generally, in laboratory, the sizes of rubber stopper can be varied up to approximately 16 sizes and each of it is specific to certain type of container. As the rubber stopper is used in many experiment, some specific experiment requires a specific material. For example, the M35 Green Neoprene is for chemical resistance. For food fermentation, M18 white natural gum is preferred. For high temperature application, red or white silicone rubber stopper should be used.
Sizes
Rubber bung can have one or more hole for plugging in tube depending on the specification of the procedures. To prevent the liquid chemical leaks or escape the container, the rubber bung should fit tightly to the container's opening; therefore, the dimension of the rubber bung is of concern. These are some of the sizes that are commonly seen in chemical laboratory.| Size No. | Top mm | Bottom | - |
| 000 | 12.7 | 8.2 | 12x75 test tubes |
| 00 | 15 | 10 | |
| 0 | 17 | 13 | |
| 1 | 19 | 14 | |
| 2 | 20 | 16 | 20x150 or 10ml test tubes |
| 3 | 24 | 18 | |
| 4 | 26 | 20 | 25x200 or 20ml test tubes |
| 5 | 27 | 23 | 50 ml Flasks |
| 6 | 32 | 26 | 250ml Erlenmeyer Flasks |
| 7 | 37 | 30 | 500ml Erlenmeyer Flasks |
| 8 | 41 | 33 | 1000ml Erlenmeyer Flasks/ Florence Flask/ Filter Flask |
| 9 | 45 | 37 | 1000ml Erlenmeyer Flasks/ Florence Flask |
| 10 | 50 | 42 | 1000ml Filter Flasks 2000ml Erlenmeyer Flasks/ Florence Flask |
| 11 | 56 | 48 | |
| 12 | 64 | 54 | 4000ml Filter Flasks |
| 13 | 68 | 58 | |
| 14 | 90 | 75 | |
| 15 | 103 | 83 | |
| 16 | 127 | 90 |