LightJunction.com products video reviews - The TD15 is a variable-output flashlight that provides four mode of light output. It uses a super bright CREE XP-G R5 LED and a precision reflector to produce a consistently smooth beam at any level. By loosen and tighten the head twice in 0.5 second to switch between normal mode and tactical mode (total five output level) - lowest for longest run time at 20 lumens, highest for maximum light at 420 lumens, and strobe for tactical. Its push button tail-cap click switch provides secure, ergonomic activation control: press for momentary-on, click for constant-on. The TD15's crenelated strike bezel and scalloped tail-cap provide further defensive options should the need arise.