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
Eisco™ 2 Hole ASTM Neoprene Stoppers
Pack of ten 2-hole ASTM neoprene stoppers. Made from long lasting neoprene rubber. Oil resistant, use up to 250°F / 120°C. Suitable for use with petroleum products, minerals, oils, fats as well as most inorganic acids.
United Scientific™ Neoprene Stoppers
Used in areas where rubber would be attacked by reagents or solvents. Neoprene Stoppers have good resiliency and shelf-life.
United Scientific™ Rubber Stoppers, Solid Version
Ideal for use with non-aggressive or concentrated solutions.
Eisco™ Polypropylene Flat Head Stoppers, Multipack
Acid-proof, autoclavable, and come in a variety of joint sizes
Eisco™ Solid Rubber Stoppers
Solid orange rubber stoppers for use in science laboratories.
United Scientific™ Rubber 2-Hole Stoppers
2-hole, Size No. 2 to 8
United Scientific™ Rubber Stopper Assortment
This Rubber Stopper Assortment includes assorted styles, size numbers 1 to 6.
Eisco™ Solid Neoprene Stoppers
Pack of ten solid neoprene stoppers. Made from long lasting neoprene rubber. Oil resistant, use up to 250°F / 120°C. Suitable for use with petroleum products, minerals, oils, fats as well as most inorganic acids.
Eisco™ Solid Glass Flat Head Stoppers
Solid glass flathead stoppers are made from high quality borosilicate glass, and come in a variety of join sizes.
United Scientific™ Neoprene Stopper Assortment
Used in areas where rubber would be attacked by reagents or solvents. Neoprene Stoppers have good resiliency and shelf-life.
Eisco™ Rubber Stopper
With one hole in bottom
Twistit: Four Stoppers in One
Multi-purpose and economical
Chemglass Life Sciences Septum Stopper, Sleeve Type, For 24/40-24/25 Outer Joints, White
Septum Stopper, Sleeve Type, For 24/40-24/25 Outer Joints, White. Sleeve type stoppers with a hollow plugs and sleeve extensions that folds down over the neck of a vessel, tubing, etc. The diaphragm can be punctured with a syringe needle, re-sealing after the needle is withdrawn.
