Great for checking notes, credit cards, fluorescent inks (invisible inks), cracked glassware, or even crime scene. Strong in UV, but not strong in visible light. The body of this flashlight is built of high quality aluminum alloy, and it has a very solid construction. Internal wiring applies the high efficient booster circuit, and can utilize the batteries in the largest extent. Excellent waterproof, suitable for outdoor environment, adverse weather conditions. Emitter Type:UV LED WL(wave length): 385~400nm Bulb Quantity: 9 Lightbulb/LED Lifespan: 10,000 hours Modes: 1 Battery Configuration: 3 x AAA batteries (NOT INCLUDED) Input Voltage: 4.5 v Runtime: About 4.5 hours Switch Type: Clicky/Clickie Switch Location: Tail-cap Lens: Coated Glass Lens Material: Aluminum Alloy Body Color: Blue, Red, Silver, Black Dimensions(L x Head Dia. x Body Dia.):3.62 x 1.06 x 0.98 inch /9.2 x 2.7 x 2.5cm Weight: 63g / 1.94oz Package Includes: 1 x 9 UV LED Ultra Violet 385~400nm Blue Flashlight Torch