I haven't found a pen light that's any good. all are of bad quality. But, maybe it's one of those things "you get what you pay for." The components that turn the light on, seems to always be in the on position, which runs the batteries down. . . Almost waiting for the time when you need it the most, like insertion of a G-tube and you need to see which nostril is the best. My latest, pen has a sleeve on it that prevent the light form going on