Dead blow uni-cast dead blow hammer, shockless hammer 1/2 pound = approx. 230g PVC Unused This hammer has a non-rebound structure that effectively transmits impact force. The PVC resin head makes it less likely to damage the target. A shockless hammer is designed to alleviate hand numbness and pain. It is also called a non-rebound hammer or dead blow hammer. As the name suggests, it reduces shock and recoil during impact, and furthermore, generates strong impact force with less effort, and is also quiet. It's no exaggeration to say that it's the ideal hammer. The principle is that the hammer head has a hollow interior containing small metal balls or pieces.