Comparison AMS A4221 vs AMS A4191

The diameter of the sensors supplied as standard with the parking radar is an important parameter when installing them: it determines the size of the landing slots, in other words, the holes in the bumper. Many parking sensors are equipped with a special cutter for drilling such sockets — it optimally matches the diameter of the complete sensors, and in this case this parameter actually becomes irrelevant. However, if there is no cutter in the kit, you will not be able to select the drill of the right size without information about the diameter. Also, this information will be very useful if you install parking sensors on a car with existing holes in the bumper (for example, if the previous radar did not suit you according to its characteristics): by choosing a model with the same sensor diameter, you can install them directly into ready-made sockets, without too much fiddling with the fit. So the most popular sensor size is 18 mm, but there are 19, 20, 21 and 22 mm. In this case, often in each option there is a deviation of half a millimetre.