SW24UU Seals on both sides NB Nippon Bearing Linear Systems Made in Japan SW24UU 1 1/2" Bore linear motion ball bushings/bearings, SW24UU is Seals on both sides, inner diameter(bore) is 1 1/2" inch dimensions with steel retainer, Bearing is a high accuracy grade linear bushings, series mainly used in the USA, NB brand (Nippon Bearing Linear Systems), made in Japan.