Princeton Tec Impulse Lights. The tiny Impulse is jam-packed with big features! It has 5 electronic switch settings, including low, medium and high beam, and fast and slow blinking modes. With its quick release, detachable clip and hat clip option you"ll want one for every keychain, backpack, ball cap and book bag in the house!Burn time of 36 hours10 LumensCompact, water resistant, and self-contained14g with batteriesIncludes 2 2016 Lithium Coin CellItem SpecificationsWeight14gBattery2016 LithiumBulbLEDRun Time36 hours