I found this on candlepowerforums dot com
With the head fully tightened, activation yields Turbo only.
For general mode, starting with the head slightly loosened, click on to activate High output. Soft-press to advance to Med. -> Low -> Ultra Low -> Strobe in sequence.
If you turn the light off-on within 1 second, you will advance to the next output (i.e., acts as a soft-press). If you wait longer than that, you will return to the last output level used. The light has mode memory (even after a battery change).