AMP Research 2004-2007 Ford F-250/350/450 SuperCrew PowerStep XL -

Amp Research PowerStep(TM) XL Running Boards take the style and convenience of traditional running boards to the next level. As the name implies, these automated boards extend when your cab door is opened and tuck away when the door is shut. The extending and retracting happens quickly - in less than a second - so you're not waiting around. Unlike the base Powerstep model, these are designed to hang even lower - making them great for lifted trucks.