Description
Product Overview
The Karter Scientific Size 11 cork stoppers are engineered to meet the rigorous demands of modern laboratory environments. Crafted from premium natural cork, each stopper exhibits the XXX quality designation, indicating superior density, elasticity, and resistance to compression set. The stoppers feature a top diameter of 26.9 mm, a middle diameter of 23.5 mm, and a bottom diameter of 21.0 mm, providing a precise fit for a broad spectrum of glassware, including flasks, beakers, and test tubes. Their length of 31.8 mm ensures a deep seal that minimizes the risk of leakage during prolonged experiments or storage. The product dimensions of 0.83 × 0.83 × 1.25 inches and a lightweight 2.54 oz design make handling and inventory management straightforward, while the pack of 25 offers a convenient quantity for routine laboratory use.
These cork stoppers are compatible with standard laboratory equipment and are designed to maintain a hermetic seal even under temperature fluctuations and chemical exposure. The natural cork material is chemically inert, reducing the possibility of contamination and preserving sample integrity. Additionally, the stoppers are reusable, allowing laboratories to reduce waste and operational costs over time. The Karter Scientific brand, recognized for its commitment to quality and reliability, ensures that each stopper undergoes strict quality control testing before it reaches the end user.

Usage
In research laboratories, these cork stoppers are ideal for sealing reaction vessels during synthesis, titration, and incubation processes. Their robust sealing capability supports both static and dynamic applications, such as gas evolution studies or vacuum distillations, where maintaining a leak‑free environment is critical. The stoppers also perform well in educational settings, providing students with dependable equipment for hands‑on experiments in chemistry and biology courses.
For quality‑control laboratories, the consistent dimensions and material properties of the stoppers enable reproducible results across multiple test runs. They are suitable for use with analytical instruments that require sealed sample containers, such as spectrophotometers and chromatographs, ensuring that sample exposure to ambient conditions is minimized. The stoppers’ durability allows them to withstand repeated insertion and removal cycles without significant wear, extending their service life in high‑throughput environments.
In industrial applications, the cork stoppers can be employed for sealing small-batch reactors, pilot plant equipment, and custom‑fabricated glassware. Their ability to accommodate slight variations in glassware dimensions makes them a versatile choice for engineers and technicians who need reliable sealing solutions without the expense of custom‑made components. The stoppers’ natural cork composition also offers a degree of thermal insulation, which can be advantageous in processes that involve temperature-sensitive reactions.
Why Choose Us
Karter Scientific has a long history of supplying high‑quality laboratory consumables, and these cork stoppers are no exception. Each stopper is produced using a controlled compression process that preserves the natural elasticity of cork while eliminating voids and imperfections that could compromise sealing performance. The XXX quality rating is the result of rigorous testing for compression resistance, dimensional stability, and chemical compatibility, ensuring that the stoppers meet or exceed industry standards.
Our commitment to sustainability is reflected in the use of responsibly sourced cork, a renewable material harvested from cork oak trees without harming the tree itself. This eco‑friendly approach not only supports environmental stewardship but also provides a product that is biodegradable at the end of its useful life, aligning with the growing demand for greener laboratory practices.
Customer support is a cornerstone of the Karter Scientific experience. Our technical assistance team is available to help users select the appropriate stopper size, troubleshoot sealing issues, and provide guidance on best practices for storage and reuse. We also offer a straightforward return policy for any defective items, reinforcing our confidence in product quality and customer satisfaction.
By choosing Karter Scientific cork stoppers, laboratories benefit from a combination of reliable performance, environmental responsibility, and responsive service that together create a value proposition unmatched by generic alternatives.
Key Features
- XXX quality natural cork ensures a tight, leak‑free seal for critical experiments.
- Precise dimensions (26.9 mm top, 23.5 mm middle, 21.0 mm bottom) fit a wide range of glassware.
- Reusable design reduces waste and lowers long‑term laboratory costs.
- Eco‑friendly, responsibly sourced cork supports sustainable lab practices.
- Dedicated technical support and hassle‑free returns provide peace of mind.
FAQ
What types of glassware are compatible with these cork stoppers?
The stoppers are designed to fit standard laboratory containers such as flasks, beakers, test tubes, and custom glassware that match the specified top, middle, and bottom diameters. They work well with both round‑bottom and flat‑bottom vessels.
Can the cork stoppers be sterilized for use in microbiology applications?
Yes, the natural cork material tolerates autoclaving at typical laboratory temperatures. However, prolonged exposure to high humidity may affect elasticity, so it is recommended to allow the stoppers to dry completely before reuse.
How many times can a single stopper be reused before it needs replacement?
When handled properly, a cork stopper can be reused dozens of times. The exact lifespan depends on the frequency of insertion, the chemicals involved, and storage conditions. Visual inspection for cracks or compression loss is advised.
Are there any chemical compatibility concerns with these cork stoppers?
The cork is chemically inert to most aqueous solutions, organic solvents, and gases commonly used in laboratory settings. For highly aggressive acids or bases, it is prudent to verify compatibility with the specific chemical before prolonged contact.
What is the packaging format and how is it suited for inventory management?
Each package contains 25 individually wrapped stoppers, allowing easy counting and minimizing contamination. The compact box dimensions facilitate storage on shelves or in cabinets, and the clear labeling aids quick identification during ordering and restocking.







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