Aluminum Frame, Graphite Sideplate, Graphite Rotor, Aluminum Spool are a short list of features you get with the smooth 6 bearing Shimano Saros spinning reels.  All models of the Shimano Saros spinning reels have 5 Shielded ball bearings and 1 roller bearing, Waterproof Drag, Maintenance Port and Paladin Gear Durability Enhancement.
The Shimano SAR1000F is 5.6 to 1 ratio, The Shimano SAR2500F and Shimano SAR3000F are 6.0 to 1 and Shimano SAR4000F is 5.7 to 1.

Look at all the other features of the Shimano Saros spinning reels. 

Propulsion Line Management System: Propulsion Spool Lip, SR One-Piece Bail Wire, Power Roller III, Redesigned Bail Trip, S-Arm CamSlow Oscillation, SR-Concept: SR 3D Gear, SR One-Piece Bail Wire, Spare Aluminum Spool, S-Concept: S-Rotor, S-Guard, S-Arm Cam, Machined Aluminum Handle, Direct Drive Mechanism , Septon Handle Grip, Fluidrive II, Floating Shaft, Dyna-Balance, Super Stopper II, Repairable Clicker, Approved for use in Saltwater, Rated for use with mono, Fluorocarbon and PowerPro lines.

Model	Retrieve Per Crank	Line Capacity
SAR1000F	28	2/270, 4/140, 6/110
SAR2500F	34	6/200, 8/140, 10/120
SAR3000F	34	6/230, 8/170, 10/140
SAR4000F	37	8/240, 10/200, 12/160