AuKvi Red Light LED Flashlight Zoombale Red Hunting Light Torch,Single Mode Long Range Red LED Red Light, Waterproof Red flashlight Torch Best for Astronomy, Aviation, Night Observation,etc

Product is solid and well built. Light is very bright and focused. Great for checking outside.

Decent product for the price. Not the brightest or longest reaching beam of light but will get you through in a pinch. I attached it to my shotgun for a gun light and use my foxpro light as a scan light. This light will do the job.

Works well

Color is as advertised as a far red, roughly centered around 660-665 nm visually in a spectroscope. VERY bright as the driver IC runs at around 1.25A, which gives a high light output. But reduced battery and LED life and some heat in operation. Also since its a red LED it will work well with NiMH AA batteries and the included holder, but is a bit much for standard AA's. One minus is that the IC does not cut off until it reaches nearly the forward voltage of the LED, which means any Li ion 18650 battery will need to be a protected cell or it will over discharge it.

I used a spectrometer in our shop to check the 2 units I got. Both have a peak wavelength of 668-669nm with a central wavelength closer to 665nm. That should be good for LLLT at 670nm. In the chart, the green line is 670nm. I was also able to measure the output power at about 200mW. You can use that and the fraction of the output that's actually entering your eye to calculate the dosage. I hold it at arms length set for the largest spot and keep my eye's closed and it's bright but not uncomfortable. The higher power is good for deep tissue LLLT. I'm using them at full power on a trick knee. Too early to say whether it's helping though.