The key to saving weight in your pack is making sure everything you carry has at least 2 uses, the Noctilight from Petzl fits this rule to a tee, turning your headlamp into a lantern when you don't want it on your noggin.
Whilst in your pack, it's a zippered protective case for your headlamp, then when you get to camp it doubles up as a lantern that can be placed on a flat surface, hung inside a tent or carried around, simply place hour headlamp inside, turn it on, and the Noctilight provides a diffused area light.
The Noctilight is compatible with Petzl TIKKINA, TIKKA, ZIPKA, ACTIK, ACTIK CORE, REACTIK, REACTIK +, TACTIKKA, TACTIKKA + and TACTIKKA +RGB headlamps, and can also be used with other headlamps of similar dimensions.