This is either done by a cable or done electronically. When you push down on the accelerator pedal a valve inside of the throttle body will move accordingly allowing more or less air to be entered.
This item is in the category "Vehicle Parts & Accessories\Car Parts & Accessories\Air & Fuel Delivery\Throttle Bodies". The seller is "mr-wiper" and is located in this country: GB. This item can be shipped to all countries in Europe.