This hammer is 12" long with 1 1/2" heads. A hammer head is a permanent metal head that I won't be using very often as I would rather use my smaller claw hammer when I need a smaller metal head hammer. The other side of the hammer head is designed for one of three different colored plastic hammer heads that screw on. But the only difference between these hammer heads that I can point out is their color. I can't tell any difference in softness/hardness between these plastic hammer heads. And the packaging gives me no idea of their hardness/softness differences. So when I need a softer sledge hammer, I use one that matches the color of my shirt that day (just kidding :-)).