Specifications: GX1000, GX2000, GX3000, GX4000, GX5000, GX6000, GX7000. -Magnetic braking system and precisely matched brass gears. Transmission ratio: 1000-5.1:1. Ball bearings: 13+1. (4) Corrosion resistant armored ball bearings with ultra smooth operation, recyclability, and long lifespan.