This ceramic ring is the top insulator in the upper nozzle section of the Non Contact Cutting Head on a Mark II or NTX. Fits between the Central Copper Body (M114U0) and the Brass Base (M111B0). The ceramic version breaks easier then the teflon version, but it withstands heat better than teflon.
Mazak® Part # 46683302081 / 46683301080-C.