This is a very nice cross peen style sheet metal hammer with the steel shaft, and leather compresses washer type handle. The metal plate on the end of the handle is marked "ESTWING ROCKFORD ILL. MADE IN U.S.A.12 oz HEAD PAT 18829" (One of the 8s may be a 6, not sure). This is a vintage hammer for the mid-1900's era, but is still in very nice shape overall. The leather handle is the leather oblong washer type, for the best grip you can buy.  There is a few minor flaws in the leather washers, but they are compressed well enough to where there is no movement of the leather grip overall. The hammer head is 4.7" long, 5/8" wide and the handle is 11.5" long. A very well made hammer!