Drilling Rubber Stoppers
Drilled rubber stoppers provide a passage for an airlock, blow-off tube or other fitted component while closing the surrounding vessel neck. Two fits matter: the outside of the stopper against the vessel, and the bore around the inserted tube. Neither should be selected from the stopper number alone.
Measure the vessel opening and the outside diameter of the tube or airlock stem. Compare these with the stopper’s tapered dimensions, bore diameter and bore position. Leave sufficient rubber around the hole, and check that the installed stem does not interfere with the vessel or prevent the stopper from seating.
In a fermentation arrangement, keep the intended gas-release path open and check the assembled connections for leaks. Choose the material for the contents and cleaning method. A stopper with a hole is not a universal pressure-relief device, and one bore size will not necessarily fit every airlock.
All dimensions are in mm
Stopper & Plug Size Catalog
Compare four stopper profiles and check the selected part dimensions against your opening and available depth. Each profile has its own drawing and dimension meanings.
Custom colors are available to your Pantone color code. Include the code in your inquiry.
RST T-Shaped Plugs
Match stem diameter A, flange diameter B, stem length C and flange thickness D. E refers to the underside recess; use the selected row and approved drawing to confirm the actual profile.

RSA Tapered Corks
Compare large-end diameter A, small-end diameter B and Height, in mm. The mating bore and required seating depth determine where the taper contacts the opening.

RSB Undercut Plugs
Compare neck diameter A, flange diameter B, flange-to-lip distance C and flange thickness D. Check panel thickness and rear clearance. E refers to the underside recess.

RSD T-Shaped Stoppers
Compare stem diameter A, flange diameter B, stem length C and head thickness D, in mm. Check the seating surface and available depth as well as the hole diameter.

Need a different fit? Share the opening dimensions, mating profile and intended use for a custom size.
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