The BES MAG6589 "Magnafish" pulls wire through existing walls using a magnetic paddle on the outside and a magnetic leader in the inside. Includes 10' ball chain and durable foam lined carry case. Leader Magnet will also screw onto our Fiberfish or Glowfish Rods for added control of the magnet. Do not use on live circuits. Strong magnets can cause damage to hard drives and monitors. One year warranty.