I took this off my Surefire E1L Outdoorsman...so, per Surefire's website, it should fit the E series flashlights. I replaced this unit with a new one b/c it is sometimes a little tough to engage. That being said, both the momentary and on/off switch work, it just sometimes takes a little extra pressure. I have no idea why. I can see no visible wear on the switch (it's only about a year old).