The #10.5 Drilled Rubber Stopper (DRS) is a pure white gum laboratory stopper. The top diameter is 2 1/16", the bottom diameter is 1 3/4", and it has a 3/8" hole drilled in the center, the perfect size for an airlock.
The #10.5 Rubber Stopper is also available as a #10.5 solid rubber stopper (srs).
