The Inova Microlight is an ingenious precision engineered micro LED flashlight with surprising performance. From its tough polycarbonate construction to its multi-function switch mechanism to its LED lamp, the Microlight is subtle but very effective. Powered by 2-2016 Lithium coin cell batteries the Microlight offers advanced design & engineering in a key holder-size lighting instrument with up to a 50-foot effective range & up to a one-mile signal visibility. The Microlight also features four lighting functions & a water-&-crush-resistant body, plus a stainless-steel universal clip that attaches easily to keys, zippers, purses, backpacks, military gear & any number of convenient locations. This is the blue light version, has up to 15 hours burn time & will operate from -20c to +40c