In case anyone’s thinking of it, it’s the same(?) as the UF DV-S9 which I looooooove. (See my gushing over this light in its own thread. Ultrafire DV-S9 diving light? )
Don’t do a “leave it and forget until you need it” on this light, though. The magnetic switch (Hall-effect IC) has a 10mA (exactly) parasitic drain, so do a TCLO (tailcap-lockout) on it. ¼-turn is plenty.