a typical manual transmission vehicle, with (for example) five forward gears, will thus have seven possible positions: the five forwards gears, reverse gear, and a central "neutral" position. some vehicles have a special button to prevent accidental engagement of reverse. others require that the lever be lifted, pressed down, or moved with extra force to engage reverse. in transmissions with reverse directly below fifth, there may be a mechanical lock-out preventing selection of reverse other than from neutral, thus preventing a driver used to a six-speed transmission from engaging reverse while trying to select sixth. some transmissions also have an electronically controlled error-prevention safeguard that blocks the first and sometimes the second gear from being selected if the vehicle is moving fast enough to exceed the engine's maximum rpm.