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.