Gen 2 Rotors are fully enclosed, which eliminates trash build-up and have a staggered bar design, allowing a more even flow of material and more even threshing as material passes over the concaves. The evenly distributed material also reduces the impact on the concaves, reducing wear of the concave. They are more heavy duty, allowing inertia to assist in rotation reducing fuel consumption. Boron Bars – 16 Narrow and 16 wide Boronizing, is a thermo-chemical hardening process used to improve the life and performance of metal components to strengthen resistance to corrosion and abrasive wear.