NB SW20 1 1/4 inch Ball Bushings Linear MotionSW20: Made in Japan: NB Linear Systems Nippon Bearing Linear Systems SW20 1 1 4" Bore linear motion ball bushings bearings, SW20 inner diameter(bore) is 1 1 4" 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. The NB slide bush uses a round shaft for the guide, resulting in effective space utilization, which allows for compact