The Adjustable Spanner (also known as a Crescent Wrench, Swedish Key, or Monkey Wrench) is a wrench with adjustable jaws capable of grabbing onto bolts of multiple sizes, making it an essential tool in assembling and upgrading the Konig. One can initially be found in the garden shed outside the Player's Home, but more can be obtained by various means.
When equipped, all 12mm and 20mm bolts in the area will glow with a light blue color, making them especially easy to spot in dark, muddied places. This blue glow can be seen through most solid objects like walls and vehicles, but any bolts fully tightened to the Konig can be obstructed. By default, holding the Left Mouse Button will tighten a bolt, and holding the Right Mouse Button will loosen one. While doing so, a percentage value will appear on screen, showing how tight or loose any bolt is.
In addition to the spanner the player already owns, one can be found for free atop a wind turbine at the Wind Farm, and more can be purchased from Kali-Gas for $32.99 each.