Packed with new features, but built on a traditional frame, the Sustain FE is the perfect balance of old and very, very new. While the frame and spool are aluminum, the rotor and sideplates are graphite. The spool lip, however, is titanium to minimize wear and protect all types of fishing line. But look inside and you'll see the technology that Shimano® is known for. The Paladin Gear Durability Enhancement uses a cold-forged aluminum drive gear with a special hardened brass pinion gear. That combination gives a durability greater than stainless steel with a smooth retrieve that comes straight out of the box and lasts. You also get greater casting distance and accuracy with the Propulsion Line Management System. It uses a propulsion spool, SR one-piece bail wire, Power Roller III, redesigned bail trip mechanism and S-arm cam, along with the Aerowrap II Oscillation worm gear for unmatched casting distance and accuracy. These components work together to cut down on friction and increase efficiency so more energy is tranferred to the line. Shielded S A-RB bearings use either rubber or stainless steel for protection. The machined-aluminum handle threads into the direct drive mechanism to eliminate play and increase transmission of power. The waterproof drag keeps moisture, sand and dirt locked outside. Maintenance port for easy lubrication of the drivetrain. Septon handle grips. Stopperless design on 6000 and 8000 sizes only.