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

Specs:

Teeth: 17/23

4.11 Gear Ratio: Low 3.04 High 5.56

4.12 Gear Ratio: Low 3.05 High 5.57

4.57 Gear Ratio: Low 3.38 High 6.18

4.86 Gear Ratio: Low 3.59 High 6.58

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