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

Specs:

Teeth: 18/23

4.11 Gear Ratio: Low 3.22 High 5.25

4.12 Gear Ratio: Low 3.22 High 5.26

4.57 Gear Ratio: Low 3.58 High 5.84

4.86 Gear Ratio: Low 3.80 High 6.21

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