WOW.. This is cool, a vintage brass or bronze plumb bob.  The bob is 2-3/4" long, with the string holder its 3-1/3" long.  The bob is 1-1/2" wide. 

The bob looks to be made up of two parts, they move a little. But it will not come a part. Thre weight is 2 OZ.  The plumb bob still has some of the old string.