VWR Black Rubber Stoppers One-Hole 12-M291 Pack. Combining top-notch and uncompromising quality with an affordable price the VWR Black Rubber Stoppers One-Hole 12-M291/ 59581-527 can fulfill your laboratory needs while still offering a great value for the money. Product Category Description: Black rubber laboratory stoppers have a hole in the center and are excellent for sealing round or square tubes. The rubber is black to easily identify the size. Stoppers feature a slightly raised heel. Excellent pliability allows shaking rocking or tapping to stop leaks. Large size is excellent for filling or removing a stopper from a container without contaminating the contents. Excellent pliability allows shaking or rattling to stop leaks. Large size is excellent for filling round or square bottles that have a single opening. However it is not recommended to seal test tubes with these stoppers as the stopper tends to break on the way in or out. Specifications for VWR Black Rubber Stoppers One-Hole 12-M291 : Size: 12 Dia. of Top mm: 64 Dia. of Bottom mm: 54 Length mm: 25 No./lb (Approx.): 6 (Please note that the description and stock photo may not correspond to the specific model listed above) We offer only genuine Plasticoid products authorized for sale in the U.S. and other markets so you can be sure that you are buying authentic Laboratory Consumables with a full manufacturer's warranty in addition to our own 100percent Satisfaction Guarantee. We are your premier online distributor for VWR Laboratory Consumables. We are an authorized supplier to all federal and state government agencies as well as to research and educational institutions and can facilitate volume orders on many types of laboratory equipment lab consumables and other products to help fulfill your specific needs. We offer Free Shipping and FREE USPS shipping to APO and FPO addresses on all orders in our store over 49. Please refer to our APO/FPO Shipping and Export Restrictions for more information on export to APO/FPO addresses. In addition to the VWR Black Rubber Stoppers One-Hole 12-M291/ 59581-527 we carry a full complement of Laboratory Consumables as well as other product offerings from Plasticoid. We also carry a full line of VWR accessories to help meet your laboratory and scientific needs. For a complete selection of VWR Laboratory Consumables please visit our Plasticoid page. For more brand name Laboratory Consumables please visit our Laboratory Consumables store section. To see our complete line of lab medical industrial and scientific products please see our science and lab equipment online catalog. VWR Black Rubber Stoppers One-Hole 12-M291 Pack