Gerber Axe Insert

An insert for the Gerber Axes with hollow handles, which makes it so you can load up the handle of the axe with all sorts of survival gear, fishing hooks, matches, Bic lighter, car key, etc. or whatever you can fit!
My friend wanted me to sharpen his axe while he was away and i thought i'd surprise him with an upgrade. I asked if there was ever a knife that clipped into the handle or anything and he said it came like that, so i looked online and most of the hollow handle Gerber axes dont have