I used to think a Princeton Tec Quad was a lightweight headlamp.
Then I got a tiny Cyclops. Great battery life, not much light.
And finally I found the Princeton Tec Scout - a bit heavier than the Cyclops but many more feaures. 3 light levels and 2 strobe speeds and still uses lithium coin batteries.
What is your favorite lightweight 3 season headlamp? Why?