This is the hugely popular Saphire light by ASP. The manufacturer guarantees the light for life for the battery & bulb. It emits a blue light, plenty bright enough to read by in the dark of night. It has a spring clip on it, so you can clip it to your trauma bag, jacket zipper, key ring, or whatever. The Firefighter light has a red body with laser engraved Firefighter scramble on one side. The EMT light has a blue body with a laser engraved Star of Life on one side.