Description of Princeton Tec Impulse LED Flashlight Never be without light again. The IMPULSE attaches to a keychain or a cap's brim. 5 modes (2 flashing) with 1 Ultrabright LED. Don’t let its size fool you – the tiny Impulse is jam-packed with big features! Powered by 2 lithium coin cells, the Ultrabright LED burns up to 36 hours and has 5 electronic switch settings, including low, medium and high beam, and fast and slow blinking modes. With its quick release, detachable clip, hat clip option, and a range of translucent colors to choose from, you'll want one for every keychain, backpack, ball cap and book bag in the house! Features: Power: 4 Lumens Lamp: 1 Ultrabright LED Burn Time: 36 hrs Batteries: 2 2016 Lithium coin cell Weight: 14 g