The hammer's mass is concentrated in the strike zone to impart as much force as possible. They are effective for driving fasteners and marring materials. Mallet heads are composed of rubber, wood, ...

The 2001 Chevrolet Corvette Mallett Hammer Z06 has been plucked out of the sinkhole at the National Corvette Museum, but it definitely couldn't drive away like the 2009 ZR1 did when it came out.