Now you have a choice of momentary or constant-on light activation without having to rotate the tailcap of your SureFire flashlight. Push lightly on SureFire Click-on Lock-out Tailcap Z61 for momentary activation, push harder to "click" the flashlight into constant-on mode, click again for off. Precision machined aerospace-grade aluminum construction, hard anodized in black. Lock-out feature of Sure-Fire Z 61 Click On Lock Out Tailcap prevents accidental activation of light during tactical operations, transportation, or storage. SureFire Z61 Click on/Off Tailcap fits SureFire Executive Series flashlights, including SureFire E1E, SureFire E1L, SureFire E2D, SureFire E2E, SureFire E2L, SureFire E2O.