The Prius is available in four trim levels - Prius II, Prius III, Prius IV and Prius V - with a base Prius I trim scheduled to arrive later in the model year. All trim levels employ Toyota's Hybrid Synergy Drive, a hybrid powertrain technology that unites a 1.8-liter Atkinson-cycle four-cylinder gasoline engine with a powerful electric drive motor to generate 134 combined horsepower, mated to a continuously variable transmission. Every Prius is equipped with a high level of standard equipment: Prius II trims feature 15-inch alloy wheels, power heated mirrors, remote keyless entry with driver door Smart Key passive entry, automatic air conditioning, cruise control, MP3 capability and driver's seat height adjustment; Prius III trims add Bluetooth wireless connectivity, satellite radio and upgraded audio with a 6-disc CD changer; Prius IV trims are further outfitted with heated front seats and leather upholstery, while the Prius V boasts 17-inch alloy wheels and auto-leveling LED low-beam headlights. Standard safety technologies include anti-lock brakes with brake assist, vehicle stability control, traction control and a tire pressure monitor, as well as dual front, front side-impact and front and rear overhead curtain airbags. An optional Advanced Technology Package offers progressive features such as a pre-collision system, radar cruise control, lane keep assist and intelligent parking assist. Hybrid-related components are backed by an 8 year/100,000 mile warranty. The Toyota Prius is completely redesigned for 2010, with fresh exterior and interior styling, more cabin room, and upgraded standard and optional equipment. A larger 1.8-liter engine with three selectable drive modes debuts, providing more power without compromising fuel efficiency, while safety is enhanced with a new driver's knee airbag and standard vehicle stability control for all trim levels. Additionally, the available moonroof now boasts solar panels that power a new ventilation system, allowing remote air conditioning so that the driver can cool the interior before getting into the vehicle.