Although the idea of the steel mace has been around for a while, my feeling is they aren't catching on due to all of what I call " Game of Thrones" stuff. There are too may coaches focussing on the weapon idea with things like swings and stabs instead of seeing the real benefit of the tool. We've taken to using the term Leverbell to denote a leverage based tool more in line with the kettle bell.
The Leverbell isn't a war instrument but rather an exercise tool that takes advantage of the ability to apply frontal ad transverse plane forces to our sagittal plane, strength training world.
The Leverbell Squat is enough of a reason to buy a few.
The addition of the Leverbell makes everyone a better squatter and, adds a really interesting anti-rotary core component to the exercise.