SMS8GUU-P Stainless Steel Anticorrosion:Miniature Slide Bush Made in Japan:NB Linear Systems Nippon Bearing Miniature Linear Systems 8mm Stainless Steel Anticorrosion Miniature Linear Slide Bush, The retainer material is resin, It is seals on both sides, SMS8GUU-P bearing is a Precision accuracy grade Miniature linear bushings, series mainly used in the USA, NB brand (Nippon Bearing Linear Systems), made in Japan.