Designed to prevent scratching or marring of the metal, thus assuring the quality of the finished piece. They are excellent for work-hardening, flattening, & smoothing metal. Made with screws rather then nails or staples to secure the rawhide roll. Hand-crafted in the USA from the finest water buffalo hides & hickory handles.  This is my go to hammer to flatten, shape or smooth most metals without marring them.