SWF10W NB:Made in Japan:NB Linear Systems Round Flange Double Wide Nippon Bearing Linear Systems SWF10W NB 5/8" Bore linear motion ball bushings/bearings, the inner diameter(bore) is 5/8" 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.