Product Specifications
Find Your Bung Size
Measure the inner diameter (I.D.) of your vessel opening before ordering. Insert the widest end of the stopper into the opening — it should seat snugly with light hand pressure. Use the table below to match your vessel to the correct size.
📏 How to Measure
- Use a ruler or calipers to measure across the inside of the opening (not the outside rim).
- Find that measurement in the Neck I.D. Range column below.
- Click the stopper size to shop that product.
Size Selector Table
All stoppers are FDA-approved food-grade silicone (21 CFR 177.2600), rated –100 °F to 400 °F (–70 °C to 200 °C), Shore A 40 hardness. Boil to sterilize.
| Size | Vessel / Opening | Neck I.D. Range | Style | Shop |
|---|---|---|---|---|
| #00 | Lab test tubes, small vials & infusion vessels | Smallest lab openings | Solid · Hole · Grab Ring | Shop #00 → |
| #0 | Lab glassware, essential oil bottles | Small lab openings | Solid · Hole · Grab Ring | Shop #0 → |
| #1 | Lab glassware, test tubes, small specialty bottles | Small lab openings | Solid · Hole · Grab Ring | Shop #1 → |
| #2 | Lab glassware, test tubes, small specialty bottles | Small lab openings | Solid · Hole · Grab Ring | Shop #2 → |
| #3 | Lab glassware, test tubes, small specialty bottles | Small lab openings — Drilled hole: 15⁄64" | Solid · Hole · Grab Ring | Shop #3 → |
| #4 | Home brewing & distilling glassware, lab bottles | Drilled hole: 15⁄64" | Solid · Hole · Grab Ring | Shop #4 → |
| #5 | Lab glassware, distilling & small-batch fermentation | Drilled hole: 15⁄64" | Solid · Hole · Grab Ring | Shop #5 → |
| #6 | Lab glassware, distilling & small-batch fermentation | Drilled hole: 15⁄64" | Solid · Hole · Grab Ring | Shop #6 → |
| #7 ⭐ | 5-gallon (20 L) glass carboys | Standard glass carboy neck — Drilled hole: 25⁄64" | Ventilator · Hole · Grab Ring · Dual-Hole | Shop #7 → |
| #8 ⭐ | Larger / newer carboys & small wood barrels | Wider carboy necks — Drilled hole: 25⁄64" | Ventilator · Hole · Grab Ring | Shop #8 → |
| #9 | 9-gallon (34 L) demijohns & small wood barrels | Demijohn / small barrel opening — Drilled hole: 25⁄64" | Ventilator · Hole · Grab Ring | Shop #9 → |
| #10 ⭐ | "Better Bottle" plastic carboys | Better Bottle neck — Drilled hole: 25⁄64" | Ventilator · Hole · Grab Ring | Shop #10 → |
| #10.5 | 2" S.S. nipples & 1 7⁄8" I.D. openings | 1 7⁄8" I.D. — Drilled hole: 25⁄64" | Ventilator · Hole · Grab Ring | Shop #10.5 → |
| #11 / ACBSV2 | 14-gallon (54 L) demijohns · 53/60-gallon (200/225 L) barrels | Large demijohn & barrel bung — Drilled hole: 25⁄64" | 5-hole vent | Contact us |
| #12 | Stainless steel tanks & oversized fermentation kegs | S.S. tank bung opening — Drilled hole: 25⁄64" | Ventilator · Hole · Grab Ring | Shop #12 → |
| #13 | Large blue tanks & fermentation kegs | Oversized tank bung — Drilled hole: 25⁄64" | Ventilator · Hole · Grab Ring | Shop #13 → |
⭐ = most common homebrewing & winemaking sizes | Sizes 7–13 are 5-hole vent style where listed as Ventilator | Sizes 00–6 drilled hole: 15⁄64"; Sizes 7–13 drilled hole: 25⁄64"
Still Not Sure?
Browse the full Tapered Silicone Stoppers / Bungs collection or contact us and we'll help you find the right fit.
Material Specifications
- FDA-approved silicone — 21 CFR 177.2600
- No TCA / TCB migration
- Temperature range: –100 °F to 400 °F (–70 °C to 200 °C)
- Boil-safe for sterilization
- Shore A Durometer hardness: 40