#4 Silicone Bung / Stopper
Our #4 Silicone Stoppers are precision-molded for high-performance sealing in both professional labs and craft fermentation setups. This size is specifically designed to fit openings with a 20mm bottom to 25mm top diameter. Whether you are sealing specialized laboratory flasks or small-scale infusion jars for home distilling, these bungs provide a secure, airtight fit that resists slipping even under pressure.
Grab Ring Variant: Features an integrated pull tab for easy removal from tight-fitting glassware, eliminating the need for prying tools that could chip or break glass.
Hole Variant (9.92mm): Perfectly sized to accommodate standard S-shape or 3-piece airlocks, making it the ideal choice for small-batch fermentation or yeast starters.
Solid Variant: Provides a 100% hermetic seal for long-term storage or chemical containment where air exchange must be completely blocked.
Pure USA Silicone: Made from high-quality food-grade silicone that is BPA-free and non-porous, ensuring it won't absorb odors or leach chemicals into your product.
Built to withstand repeated heat sanitization and chemical cleaning, these stoppers will not become brittle or lose their grip over time, providing a more reliable seal than standard black rubber stoppers.
Grab
| TOP |
BOTTOM |
HEIGHT
|
| 25 mm |
20 mm |
31.75 mm |
| 31/32" |
25/32" |
1 1/4" |
Solid / Hole
| TOP |
BOTTOM |
HEIGHT
|
| 25 mm |
20 mm |
25.4 mm |
| 31/32" |
25/32"
|
1" |
Hole Diameter = 25/64" (9.92 mm)
