This is the black aluminum ring that holds the lower nozzle assembly onto the bottom of the cutting head. It hold four set screws that are used to adjusted the nozzle centering. The outside diameter is 87mm (3.425") and the thickness is 8mm (.315"). This part is used on the Cutting Head for the Hyper Gear, HTX, Mark III, and Optiplex.
Mazak® Part # 36143300332