7 sealed precision stainless steel rust resistant ball bearings.Lifetime bail spring.Computer balanced anti-twist rotor.One-way clutch instant anti-reverse roller bearing.Right/ left interchangeable handle.Aluminum spool.Stainless steel main shaft.Hit and run system.Titanium plated anti-twist line roller.Worm shaft oscillating system.SR3007R/ 3507R with "I" type handle.SR4007R-SR6007R with power handle.