SW40 NB:Made in Japan:NB Linear Systems Nippon Bearing Linear Systems 2 1/2" Bore linear motion ball bushings/bearings, the inner diameter(bore) is 2 1/2" 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. ItemNumber of ball circuitsDimensions(Inches)Eccentricityradial clearancebasic load rating drDLBWD1 inchtolerance inch/mminchtolerance inch/mminchtolerance inch/mminchtolerance inch/mmprecision inch/mmhigh inch/mmdynamic CNstatic CoN precisionhigh SW4062.50 -.00040 -.00063.750 -.000950 -.0123.9760 -.012.123.5519.0007 17.0010 35.0005 -134,70010,0000