More than 6 million of Ford's E-Series vehicles have been built since 1960. E-Series are available in four basic styles: vans (including cargo and recreational), passenger wagon, cutaway and strip chassis. The E-Series Wagon offers three engines, while the Van and Cutaway versions offer four. In the 2007 model year, Ford is expanding Roll Stability Control to its regular-length E-350 Wagon models with the 5.4-liter engine, putting Roll Stability Control on about 85 percent of the company's passenger wagons. In addition, the Reverse Sensing System is now available with rear step or contour bumpers on E-Series Wagon and Vans. When properly equipped, the E-150 Van can tow up to 7,500 pounds, the E-150 Wagon up to 7,100 pounds, and the E-350 Super Duty and Super Duty Extended Wagon up to 10,000 pounds each. An available Class II/III/IV Trailer Tow Package includes an electric brake controller with tap-in capability, a seven-pin trailer wiring harness with bumper bracket, and a relay system for backup and running lights. Additional updates for 2007 include electronic throttle control and engine oil cooler now offered as standard on all E-Series models, larger rear anti-roll bar and increased driveshaft capacity on E-150 models to more than an 8,500 gross vehicle weight rating and new optional 135-amp alternator for 5.4-liter V-8 and 6.8-liter V-10 applications. E-250 Cutaway with 4.6-liter V-8, electronically controlled 4R75E transmission and midship fuel tank has been added to the E-Series lineup. A power equipment group is now available on all Cutaway models. Storage and cargo features include the EconoCargo System that helps protect cargo with durable panels of high-density polyethylene. This system is insulated, so the interior of the E-Series with EconoCargo retains heat and cold more efficiently, benefiting food service markets, produce farms and medical suppliers. The Masterack Work-Bin System includes fully installed steel shelving, drawers and cabinets, and a full-width security partition provides lockable access to the unit from the passenger compartment. The QuietFlex Racks and Bins System made of a composite material, providing a quieter, lighter, more flexible storage solution. The QuietFlex package includes a lockable composite bulkhead that offers the driver four inches of additional seat recline. The EconoCargo, Masterack and QuietFlex systems are available at no extra charge.