SMSF13UUE NB Round Flange Type With Pilot End Miniature Anticorrosion Slide Bush Made in Japan:NB Linear Systems SMSF13UUE NB Round Flange Type With Pilot End, Bearing is anticorrosion, Bearing is seals on both sides, The retainer material is steel, series mainly used in the USA, NB brand (Nippon Bearing Linear Systems), Made in Japan.