@James_Armstrong Are you using it above 190C ? If so, what temperature, material and printer? How is it performing? We don’t recommend over 170C as the PTFE inside is rated for 300 Celsius.
@Shai_Schechter did you mean 290c? I posted 190c and hope it can be used above 170c (what you posted) since my PLA needs 230c. I don’t ever run a PTFT lined hotend above 250c. Where is the PTFE liner? It isn’t obvious from looking at the hotend. I am assuming it is from the heat break up to the push fit?
Oops, I meant 270 Celsius. PTFE should hold up to 300, but we recommend 270C… didn’t test it over that limit.
The PTFE is inside the heatsink after the stainless steel heat break. But the heatsink should stay cool to the touch… so who knows… maybe you can go well above 300C 
Just be careful!
I could put a thermistor in the hole opposite the setscrew and measure the cold end / block.
@Shai_Schechter does the PTFE liner come out easily once the push fit is removed? I noticed the filament goes in with a little friction (couldn’t feed ninjaflex at all by hand). I have seen something similar with a MK10 hotend I have where the PTFE tube was cut a tad long and when the top is screwed in it compresses the PTFE tube changing the diameter smaller).
@James_Armstrong The PTFE comes out from the bottom of the heatsink. It’s not possible to take it out once it’s inserted… unless you drill something into it and destroy it and pull it out.
We tighten it just a bit to make sure there’s no gap between the PTFE and heat break, but we are careful about it and check it by running some filament. It will open up (settle in) once you use the hotend a bit.
@Shai_Schechter thanks. I’ll leave it be for now.