Stainless Steel Heat Break Throat for E3D V6 Hot Ends.All-Metal or  PFTE tube versionMaterial: Stainless steelRadiating end thread: M7;heating end thread: M6This heat break have 5mm deep 4.1mm dia bore on the upper (cool) side for Bowden tube to lock onas in V6.8-Heatbreak drawing from E3D. Some refer it as "Enchanced version"4.1mm trough hole version allows standard PFTE tube go whole way down to back of nozzle