Function

• Graffiti markers are used mainly for tagging, or writing on signs, walls, fences, bridges or just about any surface that is relatively smooth.
  They are best for jobs that are small and quick, taking no more than a few seconds and covering tight or compact spaces.
  Since graffiti markers cannot quickly cover large surfaces, reach strange angles, high places or feather and blend like spray paint, they are not usually mural material. Sure, they can be used for fine details or highlights once the paint is dry, but they won't be the main ingredient for larger, elaborate works.
  
  

Types

• Many types of graffiti markers are on the market, many sold as "industrial" markers rather than promoted as graffiti making devices.
  The site ArtPrimo.com showcases some of the most popular. The Drip Mop Mini is a refillable, medium marker with a plastic container and replaceable nibs. The Big Squeeze has the same features as the Drip Mop Mini, but on a grander scale. The NYC Mop marker is the largest version of the three, boasting a nib that is more than an inch wide.
  Pilot Jumbo markers are some of the most popular, sold in many hardware stores, which are metal and refillable. Pilots come with a broad, bullet, or chisel tip nib. One more metal refillable marker is the Marsh 99, which comes with an ink flow option (see Resources below).
  A marker can also be fashioned out of a plastic shoe polish bottle by rinsing out the polish and filling it with permanent ink. Black is the most popular color, by far, but other colors are available.
  
  

Benefits

• Graffiti markers are chosen over spray paint for their ultimate ease. They are easy to carry. You can shove several markers in your deep pockets; something impossible to do with a few spray paint cans.
  They are also easy to use, giving the artist full control and close contact with his easel. Markers can be maneuvered freely without any special training or considerations. Getting too close with paint will make it drip, getting too far away will have it spray too wide.
  
  

Features

• The most important feature of any good graffiti marker is what's inside: the ink. It must be waterproof, weatherproof, thick and as permanent as a bad scar. Ink is sold at art supply stores or can be made, according to an article by Curtis Fease on eHow.com, with brake fluid and paint (see Resources below).
  Another feature that plays a big part in the graffiti marker is the size and shape of the nib, or tip. Some are broad, thick and can withstand lots of abuse. Others are thinner, pointed and require a gentler hand.
  
  

Warning

• Many stores will keep graffiti markers locked up, out of reach or behind the front counter so the buyer must ask the clerk to get one out. This not only deters theft, but may also be the law.
  Under New York City's Graffiti Law, no one under 18 years of age can legally buy spray paint, etching materials or "broad tipped indelible" markers, according to NYC.gov.
  In Santa Rosa, California, a law passed requiring those same materials be locked up, behind the counter or within 30 feet and in plain view of the clerk, according to an article in PressDemocrat.com.
  Other cities have similar laws or ordinances.