Many users desire a universal wrench with the widest possible range of applications. It should be a single tool for multiple metric and imperial sizes. It should automatically adjust to different screw sizes, grip securely, cause no damage, and allow for high working speed. The continuously and parallel-guided jaws replace several individual sizes of open-end wrenches. The required size automatically adjusts when applied to the hex nut or bolt. The integrated lever mechanism securely clamps the hex screw or nut between the jaws, significantly reducing the risk of slipping and damage. The ratchet function allows for quick and continuous screwing without setting down the tool. By utilizing corner width prisms, a reverse swing angle of only 30° is achievable. The single-arm design, combined with the ratchet function and corner width prism, enables work in tight spaces. The adjustable Joker 6004 is the universal wrench. Self-adjusting. Gripping. Ratcheting.