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
Cole-Parmer Solid Color-Coded Silicone Stoppers, Standard Size 2, Pink; 20/Bag
Cole-Parmer Solid Color-Coded Silicone Stoppers, Standard Size 2, Pink; 20/Bag, Silicone bubbles make these stoppers lightweight—they float on water. Withstand temperatures from –76 to 392°>F (–60 to 200°>C).
Research Products International Corp Laboratory Grade Rubber Stoppers w/Hole, BLK SBR Rubber, Size #8 1/2, 43 x 36 x 25mm, 10 per Package
Laboratory Grade Rubber Stoppers with hole are offered in a wide range of common sizes for most laboratory applications. Available standard black SBR rubber. Material can typically withstand temperatures up to about 100°C (212°F). Rubber stoppers with hole are molded in the USA according to standard industry size specification.
Packaged in approximately one pound packages.
Research Products International Corp Laboratory Grade Rubber Stopper w/Hole, BLK SBR Rubber, Size #11 1/2, 63 x 50 x 25mm, 6 per Package
Laboratory Grade Rubber Stoppers with hole are offered in a wide range of common sizes for most laboratory applications. Available standard black SBR rubber. Material can typically withstand temperatures up to about 100°C (212°F). Rubber stoppers with hole are molded in the USA according to standard industry size specification.
Packaged in approximately one pound packages.
Research Products International Corp Laboratory Grade Rubber Stopper, BLK SBR Rubber, Size #11, 56 x 48 x 25mm, 6 per Package
Laboratory Grade Rubber Stoppers offered in a wide range of common sizes for most laboratory applications. Available standard black SBR rubber. Solid rubber stoppers are molded in the USA according to standard industry size specification. Packaged in approximately one pound packages.
Research Products International Corp Laboratory Grade Rubber Stoppers w/Hole, BLK SBR Rubber, Size #9 1/2, 46 x 38 x 25mm, 9 per Package
Laboratory Grade Rubber Stoppers with hole are offered in a wide range of common sizes for most laboratory applications. Available standard black SBR rubber. Material can typically withstand temperatures up to about 100°C (212°F). Rubber stoppers with hole are molded in the USA according to standard industry size specification.
Packaged in approximately one pound packages.
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).
Metrohm USA SCREW NIPPLE
Made of PP. For 6.1448.010 Septum or for mounting 6.1403.040 Drying tube or 6.0338.100 Electrode in 6.1414.030 and 6.1414.040 KF Titration vessel lids. Used for KF titrations.
