The Porsche Double Function Transmission offering both automatic and manual modes. In "automatic", the transmission adapts to the driver's driving style by selecting one of five shift maps. The Tiptronic® control selects a shift map while constantly measuring five variables: throttle valve opening, engine rpm, speed, lateral acceleration and longitudinal acceleration. Other unique features include a designed in reluctance to up-shift before and while cornering. In the \"manual\" mode, the spring–loaded selector is tipped forward for up-shifts and back for downshifts. Built–in safeguards prevent accidental over revving.