Here's a CR123 lithium battery for any suitable light etc. Keep one of these in each of the packs you carry, if you have equipment that uses this battery type. Or several of these if your gadget eats more.
Lithium batteries are more expensive compared to alkaline batteries. The list of benefits is long:
Nominal capacity 1480 mAh. Non-rechargeable! One pack has one (1) battery.
Varta is a trusted German brand when it comes to batteries. These batteries have an extra-long shelf-life and excellent output values throughout their life. It's always nice to see "Made in Germany" printed somewhere.