SOONORY Pen Light with Pupil Gauge LED Penlight for Nurses Doctors, Reusable Medical Penlight with Batteries for Nursing Students (White and Warm Light)

It's so clear and easy and simple. Push-button on. References for size. Fantastic. I can't emphasize enough how great it is to just have a MM/CM scale on the side of it so like when I'm looking at a wound or something I can whip out my pen-light real quick to get a good size estimate.

Works good

Worked great at the beginning