The belt capacity varies a bit. I found with the Eagle Creek one I could get in a 1L zip lock bag and some water treatment pills. My current belt is slightly narrower (by about a millimetre) and won't take the bag but will take the pills.

My current belt also has a short length of ferro rod, a half-length of hacksaw blade, and some tinder card that will take a spark. It has some safety pins and paper clips and some rubber bands. This is in addition to some paper money.

The hacksaw blade was full length, but eventually it snapped. Which is a shame as I live in an urban environment and want to be able to cut through metal in extremis. (I was also going to use it to cut my own ankle off, if ever I found myself in real extremis. I've see the Jigsaw movies.) A scalpel blade would fit, but I don't have the bottle to carry something as dangerous as that in my belt.

Basically I am currently a big believer in using money belts for every-day carry of survival items. Just having water treatment and fire-making is a boon.