SMF16UUE NB Round Flange Type With Pilot End Flange Type Miniature Slide Bush Made in Japan:NB Linear Systems SMF16UUE NB Round Flange Type With Pilot End Miniature Linear Slide Bush, 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.