Underwater Kinetics Replacement Bulb/reflector assembly is perfect when the lamp of your Mini Q40 Xenon, UK4AA Xenon Front Switch, UK4AA Right Angle Xenon, UK4AA Xenon Twist Bezel, or UK4AA Xenon Tail Switch (ATEX) light brakes down. While its Lithium bulb generates the bright light, its reflector directs the light to a specific direction. It's useful when you are searching for lost items or when you venture into dim-lit places, or when you need more light to do your task. To install, simply remove the bezel and switch the worn out lamp/reflector with this convenient replacement.