The nozzle is 17mm x 40mm thick at the front. Outer dimension. The nozzle is not extendable. It consists of two parts that are simply plugged on. You can see it well in the picture.
There is a small brush at the front with a click fastener. This can be removed. Then the tip is about 1 cm thick, but it could be a few millimetres thicker. The nozzle is extendable, so the telescope makes it a little thicker in the middle. The connection is the usual one that Miele has been using for decades.