Freddie Ramm
Could the frequency of light be displayed by a computer screen or mobile phone?
Russell Gambier
Sounds great. Where can you buy these special torches?
Wish it explained how this works and whether this deep red light is found anywhere in nature -- perhaps during sunrise or sunset?
This light isn't part of the usual spectrum coming into our eyes? Or does it for some reason have to shine alone?
Could a person not buy a pair of glasses with lenses that allow only 670 nanometer light to pass through them, and then just use any light source?
Hunters and astronomers use red flashlights. Are these the right frequency and intensity? What intensity did the research use ?
C Morgan
This is interesting. Anyone given a thought that the mitochondria in other cells might react the same?
Not suggesting that it would be the magic to restore my 76 year old body, but who knows.
I too would like to know the intensity, and also where to get this torch.
Expanded Viewpoint
Going by the photo there, all that they did was slip a short piece of PVC water pipe over one of those Chinese made LED flashlights (torches for the Limeys out there!!) they sell at harbor Freight Tools, and put a piece of transparent red plastic sheet inside. UCL should have given out where they sourced the plastic sheeting from, so those who wish to do so can duplicate their efforts.
Some of the L shaped military flashlights (torches) they use here in the Colonies come with different colored filters in the base cap. Maybe the red one is what we should be using?

Expanded Viewpoint
Just now I checked my military style flashlight (torch) and it's a Fulton MX-99/U and it came with three red lenses and two clear diffuser lenses. The diffusers make the light much more tolerable to look at. If your dry cells are brand new, you would probably want to stack in more red lenses and or diffusers to attenuate the brightness so you don't do more harm than good by staring into the light.
You can find these lights on eBay easily, and are quite the bargain there!!