These are a pair (2, one right and one left) uniballs, monoballs, spherical bearings, pillow balls....call them what you want, of bearing to replace worn parts in our, or just about any of the uniball-style upper arms on the market. These are domestic FK teflon-lined bearings, not imported nylon-lined junk. We offer these in 1" id, which fits most of the arms on the market as well as 7/8" id to fit PRG rev 1 and 2 Frontier/Xterra UCA.