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
Research Products International Corp Laboratory Grade Rubber Stopper, Black SBR Rubber, Size #000, 12.7 x 8.2 x 21mm, 183 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, Green Neoprene Rubber, Size #5, 27 x 23 x 25mm, 25 per Package
Laboratory Grade Rubber Stoppers offered in a wide range of common sizes for most laboratory applications. Available in green neoprene rubber that is resistant to chemicals and ozone deterioration or standard black SBR rubber. Solid rubber stoppers are molded in the USA according to standard industry size specification. Packaged in approximately one pound packages.
Chemglass Life Sciences Stopper, Cap Style, #9 O-Ring Joint, Airfree, Schlenk
Replacement parts for AF-0451-01. Includes one #9 o-ring joint cap stopper.
Chemglass Life Sciences Stopper, PTFE, Hollow, 19/22
Stopper, PTFE, Hollow, 19/22. Hollow PTFE stopper.
Hach Company Stopper for 18mm Tube, 25/pk
Used in multiple tests as a stopper for viewing tubes and sample cells, and as a cap for AccuVac Ampules.
Chemglass Life Sciences Stopper, Pennyhead, Hollow, 14/20
Stopper, Pennyhead, Hollow, 14/20. Hollow stopper with closed bottom.
Chemglass Life Sciences Stopper, Flask Length, Flathead, Solid, Size 13
Stopper, Flask Length, Flathead, Solid, Size 13. Flathead design allows stopper to be inverted and placed on end thereby preventing contamination of the ground surface.
Chemglass Life Sciences 45/50 Stopper, Hollow
45/50 Stopper, Hollow. PTFE stopper has a Polypropylene extraction nut permitting easy removal of the stopper from the glass outer joint. The 14/20 and 19/22 are solid, while the larger sizes are hollow.