SMSFC50GUU NB Center Mount Round Flange Slide Bush Made in Japan:NB Linear Systems Nippon Bearing Linear Systems SMSFC50GUU NB Center Mount Round Flange Linear Slide Bush, The retainer material is resin, Bearing is anticorrosion, Bearing is seals on both sides, series mainly used in the USA, NB brand (Nippon Bearing Linear Systems), Made in Japan.