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
DWK Life Sciences Kimble™ Kontes™ Hollow White Rubber Sleeve Stoppers
Hollow stopper fits into the neck of the glassware apparatus. Series 774261 may be used at up to 125°C for up to 8 hours.
Corning™ PYREX™ Solid Glass Pennyhead Standard Taper Stoppers
For use with flask and separatory funnel
Corning™ PYREX™ Polyethylene Standard Taper Stoppers
Improved design fully protects neck in event of accidental tipping
DWK Life Sciences Wheaton™ Ultra Pure Straight Plug Stoppers
Provides for extremely high chemical purity and low gas permeability. Wheaton™ Ultra Pure Straight Plug Stoppers are manufactured from an ultra pure bromobutyl formulation.
Synthware™ Solid Penny-Head Stopper
Flask length solid penny head stoppers
DWK Life Sciences Kimble™ Kontes™ Pluro Stopper Set
This autoclavable set of 7 neoprene rubber adapters is designed to fit Buchner and fritted glass funnels.
Fisherbrand™ Twistit™ Rubber Stoppers
Stoppers made from soft, resilient, natural rubber with safe convenient countersunk holes, stoppers feature excellent aging characteristics with high resistance to deformation
Fisherbrand™ Silicone Recessed Septum Stoppers
Nontoxic and autoclavable recessed septum stoppers are externally serrated to create an effective internal seal
DWK Life Sciences Wheaton™ Ultra Pure OmniFlex Plus Stoppers
Featuring PTFE-like coatings to prevent reactions due to sample contact with rubber. Wheaton™ Ultra Pure OmniFlex Plus Stoppers are manufactured in a silicone-free environment.
DWK Life Sciences Wheaton™ Sleeve Style Stoppers for Vials without Crimp Closure
Provides injection site for multiple dose entry
Synthware™ Standard PFTE Stopper
With handle for easy gripping.
Fisherbrand™ Solid Rubber Stopper for Microchemical Apparatus
Trim to fit any opening from 4 to 12mm