Upgrading to an E3D with a Bowden setup? You will need this adapter. These adapters mount into your extruder body, much like the heatsink of the E3D v6/Lite6. Run PTFE from the adapter to your E3D HotEnd and you will be up and running.
Adapters are sold individually. Chimera and Cyclops users will require two adapters, one for each extruder.