Very high quality stainless steel. Polished to a Shine. Mounted on not less quality Scotch that one side is glued to the surface of the plates. Installation must be carried out at zero temperature or warming obrabativaem the surface with a Hairdryer. Don't forget to clean the housing of the mirrors from dust and degrease, then the pads will not be afraid of any strong gusts of wind or fluctuations in humidity and temperature, no natural precipitation and car wash under high pressure.