Graffiti Supplies

I never knew that they made spray paint specifically for graffiti. In fact I didn't know there was a need for such a product. A company in Barcelona Spain called MTN (Montana) makes specific markers and spray paint for graffiti and there is a store called Art Primo where you can buy spray caps designed to give you specific lines used in graffiti. Since graffiti is illegal in most places I wonder how these products are sold openly?  And since graffiti is a street activity that uses everyday items, I wonder if there is really a market for this.

Does anyone have more information?

Is Nothing Sacred?

I just read that Los Angeles is destroying what is believed to be the largest piece of graffiti in the nation.
A contractor for the US Army Corps of Engineers began painting over the gigantic "MTA" on the concrete bank of the Los Angeles River. "MTA" stands for Metro Transit Assassians" and is 57 feet high and one-third of a mile long.

Is nothing sacred??