This is an insulating nut that sits above the nozzle tip on a Space Gear or Fabri Gear 3D Cutting Head.
Mazak® Part # 46713300321
Precitec® Part # P0352-311-00001
Disclaimer
All products are fully compatible with referenced brands, but are not affiliated with, authorized, endorsed, or sponsored by any Original Equipment Manufacturer (OEM) or named brands, unless explicitly stated in the product description.