The KRYTAC 8mm Solid Steel Bushings support the gears to stabilize rotation. Bushings are not created equal, though they look the same, the difference between one set of bushings to another is in the build materials and quality of construction. KRYTAC 8mm Solid Bushings are precision machined from steel and carefully checked for optimum performance. With no moving parts in its construction, the KRYTAC 8mm Solid Bushings allow gears to spin smoothly with maximum reliability and durability.