Store this versatile little steel wrench in your guitar case and you can quickly fix a loose output jack, control pot, pickup switch or tuning machine. Turn adjustable bridge thumbwheels more easily, too. One end of the tool can fit under a control knob and is specially angled for clearance over a guitar body or peghead. One side of the spanner is toothed for loosening a nut; the other end tightens it. A mere .075 (1.90mm) thin.