TWJ16 Clearance Adjustable Block NB Type:Slide Unit Pillow Block Made in Japan:NB Linear Systems Nippon Bearing Linear Systems TWJ16 1" inch Clearance Adjustable Block Slide Unit Pillow Block (Inch Series), bearing is clearance adjustable block, the inner diameter (bore) is 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.