Labconco Rubber Top For 120/150/300ML. Rubber tops come in a wide variety of connection configurations and are intended for use with Peterson type F glass tubes. Good manufacturing and assembly practices are observed. Before any attempt to disassemble a Coulter or similar tube it is essential that the stopper be firmly secured in place by tying the threaded end of the stopper against the threaded rim of the vessel. This avoids possible damage to the tip of the vessel from a vacuum draw down. A large gauge marks the location of the stopper. A small pilot marks the location of the vent hole on the stopper. After the rubber stopper is secured in place a few drops of water from the stopper will be sufficient to purge the borosilicate glass surface to ensure that it remains sterile. Specifications for Labconco Rubber Top For 120/150/300ML 7544200 : Description: RUBBER TOP FOR 120/150/300ML (Please note that the description and stock photo may not correspond to the specific model listed above) We offer only genuine Labconco products authorized for sale in the U.S. and other markets so you can be sure that you are buying authentic Beakers Test Tubes Flasks & Accessories with a full manufacturer's warranty in addition to our own 100percent Satisfaction Guarantee. We are your premier online distributor for Labconco Beakers Test Tubes Flasks & Accessories. 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 Labconco Rubber Top For 120/150/300ML 7544200/ 74920-002 we carry a full complement of Beakers Test Tubes Flasks & Accessories as well as other product offerings from Labconco. We also carry a full line of Labconco accessories to help meet your laboratory and scientific needs. For a complete selection of Labconco Beakers Test Tubes Flasks & Accessories please visit our Labconco page. For more brand name Beakers Test Tubes Flasks & Accessories please visit our Beakers Test Tubes Flasks & Accessories store section. To see our complete line of lab medical industrial and scientific products please see our science and lab equipment online catalog. Labconco Rubber Top For 120/150/300ML 7544200