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Securing laboratory containers effectively is crucial for preventing contamination, evaporation, and spills. The right rubber stopper ensures a tight seal, protecting your experiments and samples. Choosing the best stopper depends on specific application needs, material compatibility, and size requirements.
Complete Size Range: Includes #000, #00, #0, #1, #2, #3, #4, #5, #6, #7, #8. Each size #000 12 pieces (from #00 to #6) comes with 2 pieces, plus 1 piece each of #7 and #8
Premium Rubber Material: Made of high-density, durable rubber offering excellent resistance against non-aggressive chemicals and concentrated solutions
Secure Seal Design: Solid construction with no hole ensures leak-proof performance for flasks, test tubes, bottles, and more
Wide Compatibility: Ideal for educational, laboratory, and scientific experiments
High-Quality Material: The industrial powder coating kit is made of silicone rubber. It is sturdy, non-toxic, harmless, and good sealing is not easy to crack, it ensures a long-lasting performance
High-Temperature Resistance: Our silicone rubber plug for coating with high-temperature resistance of up to 200℃-300℃, has strong stability and corrosion resistance
Package Quantity: Rubber stoppers total include 110 PCS in 8 different sizes, sizes from 1/16" to 5/8". Color in pink, black, red, yellow, and blue, suitable for many sizes of holes used
Plastic Box Packaging: The tapered hole plug packed with a plastic box, divided into areas according to different sizes, more convenient use, and storage
【High Quality Material】Made of high-quality rubber
【Tightness】Conical design, Without hole, which fit bottle mouth nicely to keep good air tightness inside the bottle and they are easy to insert and remove.
Complete Size Range: Includes #000, #00, #0, #1, #2, #3, #4, #5, #6, #7, #8. Each size: #000 8 pieces ,from #00 to #4 comes with 2 pieces, plus 1 piece each of #5 to #8.
Premium Rubber Material: Made of high-density, durable rubber offering excellent resistance against non-aggressive chemicals and concentrated solutions.
Secure Seal Design: Solid construction with no hole ensures leak-proof performance for flasks, test tubes, bottles, and more.
Wide Compatibility: Ideal for educational, laboratory, and scientific experiments.
Material: This rubber stopper is made of rubber material, very practical, not easy to deform for good sealing performance
Sizes: Available in sizes #000, #00, #0, #1, #2, #3, #4, #5, #6, #7, and #8 for broader application options
Applications: These rubber stoppers are very suitable for laboratory and industrial use, and can be used as bottle stoppers or pipe stoppers in medicine, chemical industry, scientific research and other industries
Specifications: Our 22-piece rubber stopper set includes:6 x #000,2 x each of #00–#4,1 x each of #5–#8
Tapered Design - Smooth and tapered sides make these stoppers easy to plug and pull. All United Scientific rubber stoppers are reusable, and promote a sustainable laboratory or classroom environment.
Natural Rubber - Made from premium natural rubber, not easy to deform, elastic and great for sealing. Manufactured according to laboratory standards
Extensive Use - Rubber stopper Ideal for laboratory and industrial use, can be used to seal test tubes, flasks, etc. Available in a wide range of sizes.
Low sulfur content. Withstand temperatures from –25 to 70°C (–13 to 158°F). They do contain latex.
Complete Size Range: Includes #000, #00, #0, #1, #2, #3, #4, #5, #6, #7, #8. Each size #000 12 pieces (from #00 to #6) comes with 2 pieces, plus 1 piece each of #7 and #8.
Premium Rubber Material: Made of high-density, durable rubber offering excellent resistance against non-aggressive chemicals and concentrated solutions.
Secure Seal Design: Solid construction with no hole ensures leak-proof performance for flasks, test tubes, bottles, and more.
Wide Compatibility: Ideal for educational, laboratory, and scientific experiments.
Widely Application - The lab rubber stoppers are suitable for laboratory and industrial use, great for lab use, test tube, pipes, tank holes, and bottles. Note: This rubber cork material only for the industrial or lab use, do not use them on food or bath...
High Quality Material - Our solid rubber stoppers are made from high-quality rubber, durable and not easy to deform, the rubber stoppers plugs have no holes for good sealing performance.
Multiple Size Rubber Stopper - The rubber stoppers plugs has a wide range of 11 assorted sizes, # 000, # 00, # 0, # 1, # 2, # 3, # 4, # 5, # 6, # 7, # 8, which can meet your different needs. The rubber plug is good for flasks, test tubes, and other...
Easy to Use - The rubber corks plugs are tapered design, easy to pull and insert, reusable and has good sealing performance. Also multiple assorted size can meet your different needs. The rubber plugs are good for use with non-corrosive or concentrated...
Last update on 2026-10-16 / Affiliate links / Images from Amazon Product Advertising API
How to Choose the Best Lab Rubber Stoppers
Key Factors for Choosing Lab Rubber Stoppers
When selecting rubber stoppers for laboratory use, consider the following essential factors to ensure optimal performance and safety:
Material Compatibility: Different chemicals and temperatures can degrade certain stopper materials. Natural rubber offers good general-purpose sealing but may react with aggressive solvents. Neoprene provides better resistance to oils and some chemicals. Silicone is a popular choice for its wide temperature range and inertness, making it suitable for food and medical applications. EPDM is known for its resistance to weathering, ozone, and steam. Always check the chemical resistance charts for the specific stopper material against the substances you will be using.
Size and Fit: Stoppers are sized based on the neck of the flask or container they are intended to fit. They are typically designated by a number, with larger numbers indicating larger top diameters and smaller bottom diameters. A proper fit is critical for creating an airtight seal. Too small, and it won't seal effectively; too large, and it may be difficult to insert or could crack the container neck. Measure the inner and outer diameter of the container opening to find the correct size.
Type of Seal Needed: Consider whether you need a solid stopper for general sealing or a stopper with pre-drilled holes for inserting tubing, thermometers, or electrodes. Some stoppers are designed with specific features like tapered sides for a snug fit or lips for easier removal. For applications requiring sterility, look for stoppers that can be autoclaved or sterilized by other methods without degrading their integrity.
Frequently Asked Questions
What is the difference between natural rubber and silicone stoppers?
Natural rubber stoppers offer good general-purpose sealing and are cost-effective. However, they may degrade when exposed to certain chemicals or high temperatures. Silicone stoppers are more inert, have a wider temperature range, and are often preferred for sensitive applications or where chemical resistance is paramount.
How do I determine the correct size rubber stopper?
Stoppers are sized numerically, corresponding to the dimensions of the container neck they fit. You'll need to measure the top inner diameter and the bottom outer diameter of the container opening. Consult a sizing chart provided by the manufacturer to match your measurements to the correct stopper number.
Can rubber stoppers be used with strong acids or bases?
The compatibility of rubber stoppers with strong acids and bases depends heavily on the stopper's material. Natural rubber is generally not recommended for aggressive chemicals. Neoprene, EPDM, or specific synthetic rubbers might offer better resistance, but it's essential to consult chemical resistance guides for the specific stopper material and the chemical in question.
Are rubber stoppers reusable?
Rubber stoppers can often be reused if they remain clean and undamaged. However, for critical applications requiring sterility or to prevent cross-contamination, single-use stoppers are recommended. Always inspect stoppers for signs of wear, cracking, or chemical degradation before reusing them.
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