This blue fitting piece is part of the mechanism that drives the actuating lever, which in turn drives the grid frames. The item is an integral part of the cutting assembly and is designed to wear through time and by doing so prevent wear and tear on more expensive parts of the assembly. The fitting piece is fitted on the blade shaft and is driven by the motor. The fitting piece is made from PAS-LX which requires no lubrication or maintenance and is friction free, this helps prevent heat build up.