Silicone bungs offer a number of advantages over traditional rubber or even wood bungs. They are more durable, grippier and tighter fitting, and won't stain or absorb wine odors over time. This size bung is designed to fit a most barrels under 30 gal. We always recommend measuring your barrel's bung hole prior to purchasing. Dimensions are 1 7/8" tapering down to 1 1/4".