The 2009 Tesla Roadster's 375 volt AC induction air-cooled electric motor has an output of 248 peak horsepower (185kW) and 276 ft/lbs (375 Nm) of torque, with an EPA-estimated range of over 200 miles. Depending upon on how far the battery has been discharged and what source is being used to charge the batteries, the custom microprocessor-controlled lithium-ion battery (with 6,831 individual cells) can be recharged in as little as 3.5 hours. The Roadster uses a resin-bonded and riveted extruded aluminum monoquoque chassis with four-wheel independent double-wishbone suspension. Standard features include air conditioning, heated leather sport seats with inflatable lumbar support, CD/MP3 player with iPod interface, forged alloy wheels, power windows and remote keyless entry. The premium leather seats are available in nine colors or combination of colors. The available premium audio package includes satellite radio, navigation and 7 speaker sound system with subwoofer. Other options include microfiber cloth seats, Bluetooth cellular phone integration, matching body-colored carbon fiber hardtop with full headliner, metallic and premium paint, and a Mobile Connector for travel charging. Finally, a sports car without the guilt of exhaust emissions and poor fuel economy. The Tesla Roadster is essentially new for 2009 (a very limited number of Roadsters were available for the 2008 model year).