Our high-quality rubber stoppers are soft, non-greasy and have a durometer of 45. They are sold in a one-pound pack. These stoppers are size 5.5 and are drilled with one hole. Size 5.5 stoppers have top diameter of 28mm, a height of 25mm, and a bottom diameter of 24mm. Approximately 31 each, size 5.5 stoppers are included per one-pound pack. These lab grade rubber stoppers are soft, non-greasy with a durometer of 45. Size 5.5, 1-Hole, with a hole size of 5mm diameter. Comes in a 1lb bag of approximately 31 stoppers. Not safe for use with food products. Our high-quality rubber stoppers are soft, non-greasy and have a durometer of 45. They are sold in a one-pound pack. These stoppers are size 5.5 and are drilled with one hole. Size 5.5 stoppers have top diameter of 28mm, a height of 25mm, and a bottom diameter of 24mm. Approximately 31 size 5.5 stoppers are included per one-pound pack.