In this case, the indoor unit means the display unit — part of the parking sensors, which is responsible for informing the driver. This block is usually placed in the cabin, in plain sight — accordingly, it should match the colour of the overall design of the car. Most modern models are equipped with internal blocks
in black — this colour is very common in the design of dashboards and, as a result, is quite versatile. However, there are also other colour options.
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.
