Yes it has a low and high setting. It’s a momentary tail cap and if you twist tight, it is constant on.
Here is the wording from surefires website:
- Dual-output LED with MaxVision® Beam; delivers a broad useful wall of light that fills in the space around you
- Hand-tighten its front bezel for maximum output; loosen by a quarter-turn for low-output
- Either setting is activated in momentary-on mode with a press of the tailcap; twist for constant-on mode