NOS Beware
I deal with this stuff all the time. Usually what happens guys are looking through boxes because they don't have the books and occasionally put the wrong part in the box. Also a drawback with nos anything that has rubber in it is usually iffy. I get them and send them out to be rebuilt. Actually got lucky needed this for a customer been looking for over a year for it. On its way for a new diaphragm as I type.