Huge 21-inch Peck, Stow & Wilcox Co. Monkey Wrench
Early design with fist emblem branding (pre-PEXTO) ~1905-1915
IDEAL Type wrench available from the 1910 Catalog based on a 1905 patent and the PEXTO branding started in 1915.
Manufactured in either Connecticut or Ohio plants.

This wrench features a solid one-piece head and bar design that extends through the wooden handle.
This version is based on design improvements claimed in pat no 780,787 mostly around the threaded stem base being supported by the shoulder in addition to the split wooden handle mounting to the frame. 

Heavy, solid-built construction, weighing in at over 9 lbs.