Carboy Cap with Airlock Hole | Rubber 50 mm Stopper

50 mm Rubber Stopper with Airlock Hole

This 50 mm drilled rubber stopper is made for traditional carboy-style fermenters that need a secure opening for an airlock. If you're setting up a glass or plastic fermenter and need a simple way to vent CO2 while keeping outside air and debris out, this is the piece that does the job.

Why it works

• Pre-drilled for an airlock: ready to pair with a standard fermentation airlock
• Rubber construction: gives a snug fit in the right opening size
• Good for carboy-style fermenters: a practical replacement or backup stopper for fermentation setups

Pair it with our Double Bubble Airlock or Three Piece Airlock to complete your fermenter setup. As with any stopper, fit depends on the exact neck opening of your vessel, so it's worth confirming your measurements before ordering.