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

Specs:

Teeth: 23/29

4.11 Gear Ratio: Low 3.26 High 5.18

4.12 Gear Ratio: Low 3.27 High 5.19

4.57 Gear Ratio: Low 3.62 High 5.76

4.86 Gear Ratio: Low 3.85 High 6.13

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