Top Lock 22mm (TL22) – Top Lock Push Button measures 22mm wide on outside and 19mm on inside. There are two variations of the arm as some vehicles, the arm is offset slightly as shown in the image and on other vehicle is straight without the offset. This is standard width for most arms of this style found on Ford, General Motors and Dodge/Ram vehicles. However, On Alfa Romeo, Aston Martin, Audi, Volkswagen, and Porsche uses a wiper arm that is know as Top Lock Narrow or Slim that looks close to the Top Lock 22mm and creates confusion when installing on the vehicle. The quickest way to determine if your top lock arm measures 19mm or 16mm on inside, is to use a penny. A penny will fit snugly into the end of the wide 19mm wiper arm. It will not fit into the end of the narrow 16mm arm.