The nearest equivalent scale size I think would be Z 1:220 train gauge.
Dimensions approx 26mm long, 10mm wide and 8mm high. It is about half the size of an old Matchbox car and I have included a size comparator between a 5p coin, the Mercedes and a Matchbox Jaguar in the second last image.
A photograph of a real-life 170 S 1951 Cabriolet is show in the last image.
Made in West Germany, the model is in cream and light brown colour and has a metal body with plastic fittings and a very light, fine plastic windscreen. It is a static model that is meant as a display item and not to be 'driven'! There are no moving parts.
The tiny car is a collectors' item and is in very good condition as it has been kept as part of a collection and never considered a toy.