Coastal Alaska can be a very damp place, so I have made up a couple of first aid kits for use in wet conditions. The most recent one is in a clear plastic roll top dry bag. Most of the items inside are vacuum sealed in individual packets. For example I took 4X4 gauze pads in groups of 2 and vacuum sealed them. A few items like groups of band aids are in small zip lock bags for quick access. The clear roll top dry bag is a smallish one, readily available at places which sell sea kayak gear.

The advantage of this system is that the whole kit is protected in the dry bag. Even if my kayak gets swamped the kit stays dry. In the clear plastic roll top bag I can see the contents inside, which makes it easier to select what I want when I open it. Because the contents are individually sealed, I can open the kit even in a howling rain storm, take out what I need, and the rest of the contents are protected from moisture.

This system has worked well for me.