At One Click Purchasing, we are your reliable source for the NSN part 921-004 manufactured by Allied Healthcare Products Inc. We carry a wide range of popular NSN items on our website, including O Ring like part number 921-004 which is listed with the NSN 5331012882180 for easy identification. If you are interested in 921-004 item, then take the advantage of our online RFQ service, or peruse our website as you see fit to find other items of interest that you may wish to learn more about.