12cc Irrigation Syringe

Great for irrigation of wounds or washing eyes out.

I use this in my backpacking FAK. Out in the woods you are more likely to have some abrasions, but clean water is scarce. You could be a mile or more from a water source and only have access to the water bottles of your hiking group. This syringe lets you vary the amount of pressure you use and gives a precise stream to help clear out gunk without using tons of water.
The diameter is between a dime and a nickel and the weight is negligible so it can be tucked into almost any kit.