I had to get a new one a while back as I managed to lose the handle, unfortunately they don't float!
That reminded me of my other favourite underground tool, the 'Super Stemple®', which is half a hickory pickaxe handle, drilled through at one end for a lanyard loop and then sanded and linseed oiled every night for about three weeks. It
does float, and it was primarily designed as a climbing aid for the Titan Cascades, which are difficult to climb and easy to damage, but with some etriers clipped on it jams in the 'spout', and ignoring the torrent of water in your face, coolly climb up or down and then you just pick it up and take it with you. Note - it doesn't float with the etriers attached, as I found out at the bottom cascade, which is a metre deep - hold your breath and flail.
It's also served as a handy temporary stemple/abseil anchor in tight rifts, a hammer, a crowbar and also as discipline stick when digging. If you drop it on a concrete floor it bounces back up - what's not to like? I highly recommend one if you have a good-condition handle lying around doing nothing.
I won't even ask for royalties 😉