These resin or aluminium (on larger mod) sheaves runs on the main Composite Fibre bearing and on a ground s.steel hub: low friction highloads - no lubricant required.
The self-captive side ball bearing reduces the friction and makes disassembling, cleaning and maintenance very easy.
Sheaves serie "Composite Fibre" are used on almost the entire range of Antal block: OPF, Looper, XXL, Classic, etc.