Made of a flexible silicone rubber, this stopper or plug is designed to flush fit into round openings. It is very slightly tapered for a snug fit that will fit a 1/4 inch round hole when it is fully inserted. There is a flange at the top (see image) that measures 7/16 inch in diameter. The length of the plug from top to bottom is 3/8 inches. These are suitable for a variety of applications such as salt and pepper shakers, flat panels, plugging pipe ends and similar uses. Please Note: Measure the opening of your object carefully to make sure the plug will fit snug. A slight difference from the opening measurement shown above can be the difference between a snug or a loose fit.