670nm deep red led helps eyesight

Sofirn will also make a C01 with a 5mm 670nm red led. It is not available for preorder yet.
https://sofirnlight.com/c01-aaa-flashlight-5mm-3400k-led-95-cri-p0152.html

670nm beam might look weird.

If the final version still has this issue, you can probably fix it with d-c-fix diffusion film.

I will get one to compare, but I do not believe that there is much difference between a rated 660nm red led and a rated 670nm red led for the purposes of this thread.