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

Specs:

Teeth: 25/30

4.11 Gear Ratio: Low 3.43 High 4.93

4.12 Gear Ratio: Low 3.43 High 4.94

4.57 Gear Ratio: Low 3.81 High 5.48

4.86 Gear Ratio: Low 4.05 High 5.83

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