SWF24GWUU:Made in Japan:NB Linear Systems Sealed Round Flange Double Wide Type Nippon Bearing Linear Systems SWF24GWUU 1-1/2" Bore Sealed linear motion ball bushings/bearings, the inner diameter(bore) is 1-1/2" inch dimensions with Resin retainer, bearing is a high accuracy grade linear bushings, series mainly used in the USA, NB brand (Nippon Bearing Linear Systems), made in Japan.