What is the difference between the various colour codes on the rotary nozzles for Stihl Washers? I have a Stihl Stihl RE 127 Plus and I want a good general purpose nozzle for cleaning hard surfaces and the undersides of cars. Unfortunately the dot on the nozzle I need to replace has worn off, so that I can't see which colour it was.

The red zero-degree nozzle delivers a small, very concentrated stream of water. This nozzle is typically used for removing tough stains and debris from concrete and metal. Do not use this nozzle on wood or siding, as this stream is very strong and powerful and can damage a soft surface. The yellow 15-degree nozzle is typically used for surface preparation such as removing dirt, mildew or loose paint, and can be used on most surfaces. The green 25-degree nozzle is best used to sweep away dirt and mud. Use it to clear leaves from decks, driveways and sidewalks. The black nozzle is a low-pressure detergent nozzle. Use this when applying detergents for your cleaning projects.