LED finger light with a wavelength of 495 nm , Night-Vision NV Green 

This LED finger light is super bright and incredibly handy-literally. Designed for pilots and military personnel, it fits on your index finger like a ring and is controlled with your thumb. It’s ambidextrous, meaning you can wear it on either hand since the switches are on top.
The Velcro strap adjusts to fit any finger size and can even go over gloves.
It runs on two CR2016 batteries and is so light you won’t even notice it’s there. With an IPX-7 waterproof rating, it can handle heavy rain and tough weather conditions, though it’s not suitable for diving. You can also rinse it off if it gets dirty. It’s perfect for situations where you need focused light but still need your hands free-like flying at night, using tools, reading a map, spotting targets, or working in tight spaces.
Smart Circuit, Quality Made
The Smart Freedom Circuit allows the body switch to perform multiple functions. One button controls: instant On/Off, brightness settings, demo mode, three strobe beacons, automatic SOS, Morse code signaling, and a 3-minute timer mode.
Turquoise ("Night-Vision NV Green")
The turquoise light is slightly brighter than blue due to its lighter shade. The Covernose design provides a focused spot of light. If you want less brightness, you can swap one of the CR2016 batteries for a single CR2032. The turquoise light is a great alternative to red for preserving night vision, with a wavelength of 495 nm.