These's don't spook foxes unless they have been shot at before, when the foxes have been shot at and missed you get "about" two chance's then they wise up and it doesn't matter what I/R your using in the850nm range, they will spook-------but given time they will slip up.
Any fox that has been shot at, run with a dog and missed etc will spook with a led i/r and the bigger and brighter the led the quicker it will see it and spook. This is the reason i bought a Dragonfly in the first place, because the red signature off it is tiny. A fox would have to be directly in front of it and looking straight at it to even see it. The Dragonfly has helped me kill a lot of wary lamp shy foxes.
A discussion group for all nightvision users. Find 'Best scope for nv?' here also.