For a rectangular growing area, a linear lamp moving system is preferable. The self propelled Light Rail 3.5 Intelli-Drive is without a doubt, the finest linear lamp-mover available. It uses no pulleys, chains or gears. Simply install the standard 6 foot track over the desired area and place the self propelled motor on it. The Light Rail 3.5 Intelli-Drive comes with adjustable hooks which allow the unit to stop at the desired location.The Light Rail 3.5 Intelli-Drive will satisfy everyone from the novice gardener to the most experienced. The standard 6 foot track may also be extended. Light Rail 3.5 comes with a 2 year factory warranty. Extension not included.