Thumpers are CNC machined from straight grain Pennsylvania hickory, tapering in thickness along its length so center of mass is shifted forward towards impact zone.
The hickory surface has been rasped and hand scraped for a textured grip and comes in 2 finishes
Shou sugi ban (oiled then charred with torch)
Blood Moon (partially charred black, partially red stained)
~18" overall length and a compact cross section--this can be comfortably carried tucked inside the waistband for streamlined concealed carry (easier to do if the wearer is 5'8" or greater in height)
Ball section is ~2-5/8" diameter, nominally circular, and ~1" thick
A 3/8" diameter x ~2-7/8" long 4140 steel rod has been ground to hard cornered impact face to bite into target materials for full momentum transfer. This rod projects ~1/2" from the ball section and adds ~1.5 ounces to the impact zone. The steel had a dark patina. 
The rod is deeply inserted into the ball section--this connection is resin reinforced
The butt of the handle comes to a chisel tip for concentrated blows
Like traditional wooden warclubs, the Thumper is designed to strike target materials that have "give" to them--think flesh-and-bone, wood, and other soft targets. It is not designed for clobbering into steel plates, concrete blocks, etc.
Average weight ~ 11.5 oz +/- 2 oz