The Princeton Scout (small headlamp in foreground) I've had and use on my entire JMT (32 days no battery change)
The Princeton Tec Scout weighs 1.4 oz (40 g) with its 4x2032 coin cell batteries. It is a 2-LED headlamp with the battery housing in the front (same compartment as the lamp housing). The headband is a single strap, wrap-style with 3/4" elastic webbing.
The Princeton Tec Scout offers three brightness modes ('high', 'medium', and 'low') plus two blinking strobe modes (30 Hz, 120 Hz). Modes are toggled with a single push-button switch, designed to be pushed with your index finger while your thumb and index finger 'pinch' the lamp housing.While with heavy gloves it can be a challenge to work the little button, thin gloves worked fine for me.
What I really like about this headlamp aside from its small size is the fact that the on/off button when stowed properly can not get mistakenly engaged on. So you never have to worry about dead batteries. Its also nice and small, fits into the palm of your hand.
This headlamp is a great compact and light weight item. Great for the ultra-light backpacker. After 32 nights of consecutive use it still had enough power for summiting Mt Whitney at 1:00am, working 5 hours getting me to the top from Trail Camp. That is a winner! As was the sunrise that morning at the end of a very long and amazing JMT adventure! (smile)