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

Specs:

Teeth: 16/26

4.11 Gear Ratio: Low 2.53 High 6.68

4.12 Gear Ratio: Low 2.54 High 6.70

4.57 Gear Ratio: Low 2.81 High 7.43

4.86 Gear Ratio: Low 2.99 High 7.90

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