Winters Quick Change Gears are constructed from SAE 8620 Steel, Crown Cut, 1-3/8" Wide. 

Specs:

Teeth: 20/28

4.11 Gear Ratio: Low 2.94 High 5.75

4.12 Gear Ratio: Low 2.94 High 5.77

4.57 Gear Ratio: Low 3.26 High 6.40

4.86 Gear Ratio: Low 3.47 High 6.80

To see other gear sets available, check out the Winters Quick Change Gear Chart