SW16UU Seals on both sides NB Nippon Bearing Linear Systems Made in Japan SW16UU 1" Bore linear motion ball bushings/bearings, SW16UU is Seals on both sides, inner diameter(bore)= 1" inch dimensions with steel retainer, bearing is high accuracy grade linear bushings, series mainly used in the USA, NB brand (Nippon Bearing Linear Systems), made in Japan.