Universal stoppers have a longer taper to help produce a better fit and a snug seal, and a lip which prevents them from falling into your container. Available with a 3/8 inch hole for an airlock, or solid with no hole.
#11-11.5 (large) size is recommended for full size barrels and 14 gallon demijohns.
Universal Stopper, Large, Drilled
$2.99