The best medical kit you can bring on your next adventure is undoubtedly ... the one you bring.
Obvious ? Not quite because if you tend to overpack your kit to have it looking like the bazooka shawarma sandwich you ordered last week it wont be long until you start leaving it at home.
Today I want to go over the basic gear I'll carry in my medical kit for most adventures. I'll still modify what I carry with me based on if I have a pack or not (ski touring vs rock climbing) and on frequent/expected injuries, but this still gives an idea of what I'm carrying at a minimum most of the time.
I would suggest a size of 0,5 to 1-2 L for most of the time. A ziplock bag works fine and can be used for many other applications. If you're the kit is going to get wet or be submersed I would consider a commercial kit packaging such as one from Wilderness medical kits. I get no funding from this company I've just found the packaging their kit comes in to be durable and waterproof. But as you'll see next, dont go with the medical supplies that these kits come pre-assembled with.
Lets break down the kit contents just like the primary survey : A, B and C.
Airway
Face sheild
Nasal pharyngeal airway (NPA)