This “duplex” small serving mallet has two heads of different sizes on the same shaft. I’ve not seen one like it before, but it makes some sense. One end has a larger size, proper for serving cordage about 1 to 2 inches diameter (his head is 1 1/4 inches wide. The head at the opposite end is smaller, fit for cordage ¾ to 1” diameter, and is 1 inch wide. The shaft between them is ½ x ¾”, and is 5 ½” long, and is marked with a notch on one edge about one half of its length. There are no other marks on this tool. It is old, with great patina and is clearly a whale man’s work from the 19th Century. It is a great scrimshaw tool.