Plasticoid Black Rubber Stoppers One-Hole 7--M291 Pack. Combining top-notch and uncompromising quality with an affordable price the Plasticoid Black Rubber Stoppers One-Hole 7--M291/ 59581-323 can fulfill your laboratory needs while still offering a great value for the money. Product Category Description: For jars and flasks fitted with one-hole drilled in the cap filled with polyethylene pellets. One-hole stoppers provide leakproof seals for test tubes jars and flasks. Small size is excellent for use as a musket ball and large size is excellent for closing test tubes and jars after distillation. These stoppers with the exception of the size 1 (which is very small) are the same as the size 2 stoppers and have a more or less double sided tangential hole rather than the standard single sided tangential hole. Large size is excellent for use with test tubes jars and weighing machines as well as for storing and carrying chemical and biological specimens. Large size is excellent for use with test tubes beakers vials jars and cylinders. Specifications for Plasticoid Black Rubber Stoppers One-Hole 7--M291 : Size: 7 Dia. of Top mm: 37 Dia. of Bottom mm: 30 Length mm: 25 No./lb (Approx.): 17 Unit: Pack (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 Plasticoid 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 Plasticoid Black Rubber Stoppers One-Hole 7--M291/ 59581-323 we carry a full complement of Laboratory Consumables as well as other product offerings from Plasticoid. We also carry a full line of Plasticoid accessories to help meet your laboratory and scientific needs. For a complete selection of Plasticoid 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. Plasticoid Black Rubber Stoppers One-Hole 7--M291 Pack