Princeton Tec Impulse is small and bright and easily attaches to a keychain, backpack or almost anything; or remove the clip base and attach the light portion to the included hat clip for hands-free lighting. The Princeton Tec Impulse has 3 brightness levels plus 2 flashlight modes. The high power mode, 10 lumens, is selected by pressing and releasing the switch. Medium, low and flashing modes can be selected by pressing and releasing the switch within 1.5 seconds of the prior button press. Regardless of the operating mode selected, the Princeton Tec Impulse will turn off with one button press if more than two seconds have elapsed since the previous button press. The switch also has an automatic shut off feature (after 7.5 minutes) as well, ensuring that you won’t accidentally leave it on. With its quick release detachable clip and hat clip option, Princeton Tec Impulse is the most technically advanced personal multi task LED light on the market. You’ll want one for every keyring, ball cap, backpack and book bag……$8.50