For over 30 years, I have been using a red lens for stargazing and astrophotography, and I have changed lenses according to the evolution of technology. My experience and recent testing of several lenses can be summarized as follows:
A) If you want to buy an ultra-lightweight and high-quality rechargeable AND waterproof headlamp, but it is expensive (at €42), you can look for the NiteCore NU25 (the older model with the 2 red intensities).
B) For those who want a much cheaper rechargeable headlamp (at €13.64), they can buy the SUPERFIRE HL23-S. I have chosen this one myself after testing dozens, and it does its job excellently!!! (provided that one learns its multiple operating modes by reading the 100% informative manual)
The SUPERFIRE HL23-S headlamp turns on red with a simple double click without having to go through the position of white illumination! It also has intensity scales and a motion sensor. It charges via USB with a built-in rechargeable battery.
If you are a spelunker, ask the experts for this job and buy a much more expensive one