Named for both an old Irish agricultural tool and a piping used in early toilets, spanner wrenches have a tapered, spiky tail at one end. The main mechanism is anything from a standard fixed wrench to an adjustable grip or special fixture. The name comes from the nail part of the tool, which can be used to help line holes for bolting and welding (or for harvesting potatoes).
Its use as a standard element for hardware is credited to Thomas Maddock (1818-1899), an English inventor whose units contributed to the advancement of indoor plumbing in the late 1900s and early 2000s. He sold his "Maddock spud" wrench design to the toilet company Standard, which used it until about 1