I think they did extend the battery carrier to accept longer cells. The best protected cells would be Panasonic 3400mah (NCR18650B I think) cells with high quality PCB for lowest resistance, i.e. keeppower/redilast/kalliescustoms/orbtronic etc. Keeppower are probably cheapest.
The FF4 does have low voltage protection built in though anyway so protected cells aren’t a must unless you have a dodgy charger.
Nice info- thanks.
Since I asked Bill extra EA4 switch rubber boots and they were available only today, my FF4 should must have started its day 1 voyage only today.
Not according to Lips. It has the same carrier as the FF3.
When Xmint will have his FF4, he will surely find out since he also has the FF3.
I got the Xtar WP6 and VP1 and also NitecoreI4 II, so no problem for me.
I go for the NCR-PD
Sorry, it looks like I was wrong: FireFox IV we have lift off (Pic heavy)
I’m sure I read it somewhere though…
Well guys, the third batch of FF4s has arrived at doingoutdoor. Still at $210, plus shipping.
Bill would like to call the attention of Mr. Philipp Roth-r, one of his customers who bought an FF4. DHL is saying that his FF4 has arrived, but he cannot be contacted.
If you read this message Mr. Roth-r, please contact your local DHL office asap. Thanks
I’m assuming there hasn’t been any revisions of the FF4 over the three batches? 
I would assume that your assumption is not far out. Maybe years from now in the FF5 perhaps, as I observed of the time gap from the FF3 to the FF4. How I wish lights can be digitally reconfigurable! In my case, mine will be arriving probably 3 days from today so I will be enjoying it for what it’s worth. If something new comes up, whether in HID or LEDs, then that is another story. 
Received mine from doingoutdoor, I can’t wait to get back home to try it. Shipped May 31, 8 days to reach Canada, not bad !
Imagine a FF5 with a bluetooth controlled driver! :heart_eyes:
Lucky you! What postage did you use, if you don’t mind me asking?
EMS. Expensive but reliable. I’ve asked my girlfriend to open the package and everything is apparently there. I guess I’ll have a bright evening… 
Keep us posted! 
Nice use of a 67mm lens cap to protect the front. Carrier can use a DSLR lens carrier.
And temperature graphs comparison with FF3, current measurements, etc…
Thanks for the link…you are radiant!
German guy with photos showing Polarion PH50 vs. the FF4.
Link in CPF: Fire Foxes IV FF4 | Candle Power Flashlight Forum
Received my FF F4 from Bill @ doingoutdoor.com. Excellent service as always from this seller. I know he’s banned and the reason, but I’d have to rate them as my number 1 supplier along with Fasttech.
Very impressive light. Wish I had a decent camera to show you beamshots, but alas I don’t. Great tint colour, somewhat messy beam pattern up close, but much brighter than my bright LED lights (Supfire X40, TM26, TN30, BTU CW…) and roughly similar throw to my eyes to the BTU, TN31.
I find the handle (battery tube) a bit short for a comfortable grip, but not a big deal. The only issue I have is a colour variation in the beam of this light. There’s a noticeable blue colour visible in the centre of the hotspot.
I have the same issue with a DX sourced 65W HID and an AliExpress sourced 85W one. (Basically same as ebay HID lights.). The 2 cheaper lights are much worse; it’s just barely noticeable on the F4.
Strange to me that I haven’t been able to find any mention of the issue Googling HID flashlights.
Anyone else noticed this?
No noticeable blue tint on my one.
How does it compare to your 85W HID- same? Less?
Hopefully as your bulb burns in the blue will lessen. Totally agree re handling- it’s odd shape makes it a little hard to properly grip. A handle would have been great on this light.
Regardless, great build and huge output.
No noticeable blue tint on my one.
How does it compare to your 85W HID- same? Less?
Hopefully as your bulb burns in the blue will lessen. Totally agree re handling- it’s odd shape makes it a little hard to properly grip. A handle would have been great on this light.
Regardless, great build and huge output.