The product description of a titanium flask reads,
Appeals to anyone from the ounce-counting mountaineer to the snobby Scotch collector
What does "ounce-counting" mean here? I searched dictionaries but couldn't find a relevant result.
Ounce counting is outdoor-enthusiast jargon for minimising the weight of equipment. Heavy equipment wears out its wearer, so some backpackers, hunters, mountaineers, etc. pay a great deal of attention to how much external weight they carry. They are referred to as ounce-counting backpackers, hunters, mountaineers, etc.
Over the years I have touched on ounce counting when backpack hunting and how I’ve developed a system to help me drop significant pounds (not just ounces, but pounds) from my “going in” pack weight.
Marketers use the term as an adjective to attract their target audience of serious adventurers:
If you are the type of ounce-counting backpacker who hasn't been able to justify carrying a pillow in your pack the ergonomic Exped Air Pillow UL may change your mind.