Stopper - Rubber Bung - #9 Drilled08/19/2015 ByDavid Seymour This was just the thing I needed to convert a 5 gallon oak whiskey barrel (technically a "pin") into a secondary fermentor for beer. It came with a hardwood bung, but this enabled me to use an airlock until fermentation is entirely complete. Affordable product and shipping. Product was delivered as described, faster than expected. I will definitely do business with NorCal again. Thank you.