This is the Axial AX31405 Heavy Duty Bevel Gear Set 30T, 8T

The Axial AR44 Heavy Duty Bevel Gear Set offers improved gear mesh and reduced slop in the drive train. Machined from a high grade steel and hardened for increased strength, these gears add weight low down which helps keep the center of gravity low and on the rocks where you want it.

Features:
Improved gear mesh reduces drive train slop
Hardened steel for increased strength and additional weight in the axle
One set per axle required
High pinion design
Only compatible with AR44 axles
Genuine Axial Part