A new stopper that fits a 2.8, 3, 5, 6, or 6.5 gallon glass carboy(DOES NOT FIT BETTER BOTTLE OR PLASTIC CARBOYS). Also fits a 500ml Erlenmyer flask. Made with a longer taper from a different material, this stopper does not pop out when wet. Much more reliable, it is the stopper of choice for all applications involving these size carboys.

Also will fit a 12 or 22 oz beer bottle when used upside down!