This reusable 38 mm screw cap will fit our 1 gallon and 1/2 gallon Jugs and Growlers. It is made of plastic and has a hole in the middle, which works best with our 3 Piece Airlock. Perfect for small batch experiments or yeast starters.

California Proposition 65

⚠ Proposition 65 Warning: This product contains chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm.