Quick Specs:
SiC/Ceramic Hybrid BFS Spool Bearings
Sold Individually | Mix/Match for Your Reel

ST Models — Silent Tune/Secure Fit Technology. The outer casing is manufactured with an O-ring for a more secure connection between the bearing and reel, reducing vibrations and noise levels.
Peek Models – PEEK Polymer outer casing. 40% lighter than steel sleeve bearings. Uncompromised precision, superior concentricity.

To check sizes needed for your reel: Bearing Sizing for Common BFS Reels