Unless it's the Zombie Apocalypse I assume I'm no more than an ambulance ride away from a surgeon so I just carry a basic blow out bag to treat gunshots.
I carry a CAT tourniquet, a large pressure bandage, a roll of small gauze, some Quickclot, shears, a sharpie marker, some duct tape and a pair of gloves.
That covers my current level of knowledge so I don't carry IV bags of fluids, decompression needles or airways.
The beauty of you tube you can gain that knowledge, and the beauty of being a man your nipple is on the 4th intercostal space go one space lower and don’t angle it towards your heart