SWS20G NB Systems Ball Bushings Linear Motion 1 1/4" inch Inner Diameter SWS20G NB linear motion ball bushing bearing, bearing inner diameter is 1 1/4" inch, bearing has resin retainer, bearing is anticorrosion, Bearing is a high accuracy grade linear bushings, series mainly used in the USA, NB brand (Nippon Bearing Linear Systems), made in Japan.