SM13UUAJ Type Seals on Both Sides: Slide Bush Clearance Adjustable Made in Japan:NB Linear Systems Nippon Bearing Linear Systems SM13UUAJ Linear Slide Bush, bearing is Seals on Both Sides and Clearance Adjustable, bearing is a high accuracy grade linear bushings, series mainly used in the USA, NB brand (Nippon Bearing Linear Systems), made in Japan.