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

Specs:

Teeth: 20/29

4.11 Gear Ratio: Low 2.83 High 5.96

4.12 Gear Ratio: Low 2.84 High 5.97

4.57 Gear Ratio: Low 3.15 High 6.63

4.86 Gear Ratio: Low 3.35 High 7.05

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