When screwing in your tips, connectors or stoppers, insert this tightening key(s) into the lifeline hole found on each metal join at the ends of your TWIST & SPIN cables, connectors or stoppers. Simply use the key as a handle to help you grasp and tighten the screw connection. Use the key EVERY time you attach your tips to a cable. For an even better connection, try using our heart-shaped rubber gripper wrapped around the tip with the key. You will need the key to loosen the connection when removing the tips from the cable. Item Number: 2503-S/L (fits into our Small [S] and large [L] interchangeable cable lifeline holes) and 2503-M (fits into our Mini [M] interchangeable cable lifeline holes).