At One Click Purchasing, we are your reliable source for the NSN part 257B manufactured by Superior Valve Co. We carry a wide range of popular NSN items on our website, including Valve Expansion like part number 257B which is listed with the NSN 4820013728101 for easy identification. If you are interested in 257B 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.