4 pcs. Bought from Revain 6 months apart. 2 of them had corrosion on the brass and had to be returned from each batch. Regarding installation, they are used on a 1979 4" CJ-7. They are perfectly matched in length to allow full extension of the axles when driving. Also, they do NOT come with the necessary shims for installation, so be prepared or leaks will occur. But selling old or exposed parts is not acceptable. I will not buy from here again. Just a local parts dealer.