Sledge hammer with convex (domed) striking face Special heat treated head with a soft striking face and with a hard core The soft striking face avoids fractures or chipping and the hard core safeguards the head to the handle The unbreakable handle is made of rubber reinforced with a high carbon steel spring rod ANSI/HTI B173-1991, ASTM A576 (head), ASTM A421 (handle)