SHIMANO Sedona 500 FD Propulsion line management system: Propulsion spool Lip, Power Roller III, S-Arm Cam Redesigned Bail Trip (500 size only) Varispeed oscillation (slow oscillation on 500 size) Shielded Stainless Steel Ball Bearings Lightweight Graphite Frame Sideplate, & Rotor 2/190, 4/100, 6/60, 5, 4.7:1. By using computer balancing, an approach similar to car tire balancing, we are able to redistribute the rotor weight to create smooth rotation and eliminate vibrations caused by the reel. Dyna Balance eliminates wobble during the retrieve by counter balancing the rotor to enhance sensitivity and smoothness.