Stoppers
Stoppers, also known as bungs, are used to give an airtight seal to laboratory flasks and test tubes by fitting tightly inside the neck of the container and preventing material from spilling. Stoppers can be made of glass, cork, rubber, or silicone. They are typically designed with a conical shape, but straight, flanged, and tapered options are also available.
Stoppers are the preferred choice for many applications requiring a tighter seal or a greater degree of chemical resistance. They also provide a good seal when a solution needs to be shaken or mixed without spilling. Stoppers are generally cylindrical in shape and have a tapered bottom end. They may be marked with a stopper number or size on the top and bottom diameters of the stopper. Sizing can vary among manufacturers.
Stoppers are available in a solid design or with holes known as positions placed in the top. Positions allow easy access to the material contained in the sealed vessel by pipettes, tubing, or other equipment without full removal of the stopper.
What Types of Stoppers Are Available?
• Turnover stoppers have external serrations to create an excellent internal seal combined with a flexible turnover sleeve that folds down over the container’s neck to create a double seal
• Serum bottle or vial stoppers have two or three legs with external serrations or straight sides and a flanged top to create an airtight seal
• Straight bromobutyl plug-type stoppers provide a maximum seal for vials and serum bottles with a straight-wall glass finish
• Ultra-pure, straight bromobutyl plug-type stoppers provide high chemical purity and low gas permeability. They offer excellent performance during freeze drying processes such as lyophilization, where stoppers must remain stable during transfer and sublimination phases
• Silicone recessed septa stoppers are non-toxic and have external serrations to create an effective internal seal
Grainger Stopper Sz 0 10 mm BDia Black 0 PK50
The 16TW28 is a 16-inch diameter, two-speed, direct drive exhaust fan from Twin City Fan Companies. It features a welded steel housing with an epoxy powder coat finish and is designed for general ventilation and exhaust applications. This belt drive exhaust fan has a maximum airflow of 8,050 CFM and is available in 8 standard motor sizes ranging from 1/3 to 7.5 HP. The fan blades are made of aluminum and it can handle temperatures up to 104°F. This exhaust fan is suitable for roof or sidewall mounting.
Grainger Stopper Sz 2 16 mm BDia Black 0 PK50
The 16WC86 is a 16-ounce claw hammer by Estwing Manufacturing Company. It has a forged steel head and neck with a shock-reducing vinyl grip. The claw is curved for easier nail pulling. This American-made hammer is designed for general purpose use driving and pulling nails. It measures 16 inches long overall.
Cole-Parmer Two-Hole Black Rubber Stoppers, Standard Size 00; 113/Pk
These two-hole black stoppers made with solid natural rubber stay pliable over a long period of time. Provide good tightness and adhesion, withstand laboratory conditions without hardening, and are ideal for use with nonaggressive or low concentration solutions. Each stopper has its size marked in raised figures. Low sulfur content. Withstand temperatures from –13 to 158°F (–25 to 70°C).
MSC Nylon Cap Nut, 5/16-18 Thread, Made in USA
This nylon cap nut is designed for fastening applications where a protective and insulating cover over exposed bolt threads is required. It features a 5/16-18 thread for secure attachment.
- Constructed from durable nylon.
- Features a 5/16-18 thread size.
- Provided in a pack of 15.
- Manufactured in the USA.
Accuflow Systems Saint-Gobain Versilic Stopper, Silicone, 8D, 20 mm
Peroxide-cured silicone stoppers designed for laboratory use. These chemically and biologically neutral closures are non-toxic, odorless, non-adherent, and resistant to aging. They withstand a wide temperature range and meet common laboratory standards, making them suitable for tissue culture and general laboratory containment.
- Material: Peroxide-cured silicone.
- Dimensions: Bottom 4 mm, Top 8 mm, Height 20 mm.
- Temperature range: -70°C to 250°C (-94°F to 482°F).
- Compliance: DIN 18271, FDA/BGA approvals.
- Pack quantity: 500 per pack.
- Properties: Chemically and biologically neutral, non-toxic, odorless, non-adherent, resistant to aging.
- Applications: Tissue culture, microbiology, hematology, food science, laboratory containers.