Think an acid-etched flange hammer should be mace.

exa flange A slender wooden handle extends roughly two feet before joining a six flanged steel head. It looks as though there is a small crevice centered in between the multiple flanges that leaks minuscule amounts of an acidic substance. Shallow pits mar the surface of the hammer head but appear to leave no lasting damage. An acid-etched flange hammer is an axe, made of wood, and weighs 8 pounds 9 ounces. Currently this is shown as an axe, I'd expect it to be a mace.