The Knuckle Joint allows flexibility in the tool string for fishing operations and completion work on vertical, deviated or horizontal wells. The knuckle joint is designed for full-fluid passage for operation of tools below it, such as wash tools or fishing equipment. The tool is of a heavy-duty design and uses a primary metal to metal seal, combined with a secondary O-ring seal. Threaded connections allow the knuckle joint to be placed at the required point in the coiled tubing BHA.