Replacement single mode tail cap for Destroyer, 30LR, 38LRX, 50LR, 50LRX, 66LR and 66LRX lights. This tail cap uses a tactical switch so you can turn the light on by slightly depressing the button and as long as you keep pressure on it the light will stay on and will not make any noise or you can press the button all the way down and the light will stay on until you push the button all the way down again. Will make a click noise when you push the button all the way do