Series 40 Ball Bearing Block - Double - Swivel HeadFeatures: Low friction Acetal or Torlon bearing system; Lightweight; Cheek cut-outs for easy bearing maintenance; Features a swivel shackle head for full 360 rotation; Sheaves running on Acetal or Torlon ball bearings provide high performance & low friction. The 2-stage ball bearing system provides consistent performance over the full load range.Applications: Mainsheet; Halyard; Vang; Spinnaker control lines on off-the-beach catamarans, one design classes and sportsboats up to 8m (26ft); - cis2:mm5mnJlm -