This is a replacement HeatBreak for E3D-v6 1.75mm HotEnds.

Since v5, the manufacturing processes for all our HeatBreaks has been overhauled to achieve a better internal surface finish than ever before. The improved internal surface finish will help to reduce extrusion force and improve reliability on retractions.
NOTE:
The main threads on the heat break (middle portion) are M7x1 while the base of the heat break (goes into the heater block) is M6x1.