The Cork Stoppers – Natural Rubber from AGN Enterprises are flexible laboratory closures designed for securely closing test tubes, flasks, bottles, glass vessels, and other compatible laboratory containers. Manufactured from natural rubber, these stoppers provide an elastic fit that helps form a practical closure around appropriately sized laboratory openings.
Their tapered cork-style design allows easy insertion and removal while accommodating compatible openings of slightly varying dimensions. They are suitable for chemistry laboratories, biology laboratories, research institutions, schools, colleges, universities, pharmaceutical laboratories, and general scientific applications.
| Cat. No. | Cork Number | Bottom (± 0.2mm) | Top (± 0.2mm) | Height (± 0.2mm) | Pack of |
| AGN.6728.01 | 0 | 9 | 13 | 15.5 | 10 |
| AGN.6728.02 | 1 | 11 | 14 | 18.5 | 10 |
| AGN.6728.03 | 2 | 13 | 16.5 | 20 | 10 |
| AGN.6728.04 | 3 | 14 | 19 | 21 | 10 |
| AGN.6728.05 | 4 | 15 | 21 | 22 | 10 |
| AGN.6728.06 | 5 | 17.5 | 22.5 | 23 | 10 |
| AGN.6728.07 | 6 | 20 | 24.5 | 24 | 10 |
| AGN.6728.08 | 7 | 20 | 26 | 27.5 | 10 |
| AGN.6728.09 | 8 | 21 | 26.5 | 27.5 | 10 |
| AGN.6728.10 | 9 | 21.5 | 28 | 31 | 10 |
| AGN.6728.11 | 10 | 26 | 30 | 33 | 10 |
| AGN.6728.12 | 11 | 29 | 33 | 32 | 5 |
| AGN.6728.13 | 12 | 30 | 34.5 | 34.5 | 5 |
| AGN.6728.14 | 13 | 31 | 38.5 | 37 | 5 |
| AGN.6728.15 | 14 | 32 | 41.5 | 45.5 | 5 |
| AGN.6728.16 | 15 | 38 | 42 | 40.5 | 5 |
| AGN.6728.17 | 16 | 35 | 45 | 36.5 | 5 |
| AGN.6728.18 | 17 | 40 | 49.5 | 40.5 | 5 |
Natural rubber stoppers are commonly used as laboratory accessories where a flexible, reusable closure is required.
Unlike rigid cork closures, rubber stoppers can deform slightly when inserted into a compatible vessel opening, helping provide a close fit.
The exact dimensions, hardness, color, and natural-rubber formulation may vary according to the supplied product.
The tapered profile helps the stopper fit securely into compatible laboratory glassware.
The wider upper section prevents the stopper from passing completely into the vessel, while the narrower lower section facilitates insertion.
Correct stopper sizing is important for obtaining an appropriate fit without placing excessive stress on glassware.
Natural rubber provides the elasticity required for routine insertion and removal.
Its resilient construction makes these stoppers suitable for many general laboratory applications where a simple removable closure is needed.
Material suitability should always be checked against the chemicals, temperatures, and experimental conditions involved.
Depending on size, the stoppers can be used with compatible:
Test Tubes
Conical Flasks
Laboratory Bottles
Glass Vials
Round-Bottom Flasks
Culture Vessels
Other Laboratory Glassware
The stopper and vessel dimensions should be matched carefully before use.
Depending on availability, laboratory rubber stoppers may be supplied as:
Solid Stoppers – for closing compatible vessel openings.
Single-Hole Stoppers – for accommodating suitable glass or plastic tubing.
Two-Hole Stoppers – for experimental arrangements requiring two compatible tubes or probes.
The available configurations should be confirmed when ordering.
Natural rubber cork stoppers may be reused when appropriate for the application and when they remain in good condition.
Before reuse, they should be inspected for cracks, hardening, swelling, deformation, contamination, or loss of elasticity.
Cleaning and reuse procedures should be appropriate for the material and substances involved.
Natural rubber is not compatible with every laboratory chemical.
Exposure to certain organic solvents, oils, oxidizing chemicals, acids, alkalis, or other reagents can cause swelling, softening, cracking, or degradation.
Chemical compatibility should therefore be verified before selecting these stoppers for a specific application.
The usable temperature range of natural rubber depends on its formulation and the conditions of use.
These stoppers should not automatically be assumed suitable for high-temperature, autoclaving, vacuum, or pressure applications unless the specific supplied product is rated for those conditions.
Cork Stoppers – Natural Rubber can be used for:
Natural rubber stoppers are useful accessories for school, college, and university practical laboratories.
They can be incorporated into experimental setups involving test tubes, flasks, tubing, gas-transfer arrangements, and general laboratory glassware, provided the stopper configuration is appropriate for the experiment.
AGN Enterprises supplies laboratory rubberware, natural rubber accessories, scientific glassware, laboratory consumables, instruments, and educational laboratory equipment for schools, colleges, universities, research institutes, pharmaceutical laboratories, and industrial laboratories.
Our laboratory accessories support routine scientific work, practical education, research, and general laboratory applications.
