The preferred bubbler by many homebrewers, the S-Lock Double Bubble Airlock allows the CO2 produced during fermentation out while keeping oxygen and other baddies from getting in. Popularly used because it allows for monitoring the pressure in a carboy.
*Usage: Fill to the line with boiled water or sanitizer and connect to your fermenter of choice.
- High Quality Plastic
- Single Piece (excluding cap)
WARNING: This product can expose you to Vinyl Chloride, which is known to the State of California to cause cancer. For more information go to: https://www.p65warnings.ca.gov/
I've found the S-bubble type of airlock the most effective and dependable. Always keep spares in stock.