Sanford manufactures and markets a product line called Prismacolors. Along with a selection of capable colored pencils, the line of magic markers are the most notable. Each unit has dual felt tips. Each pen contains very exquisite pigment blends that are permanent, vividly colorful, and willing to merge with other inks to make smooth gradients are the reason for th. Art supply retailers distribute the product at a single-unit price of from $2.50 (cheap!) to $3.75. They also come boxed up (in very well engineered box/racks) in 12, 24, 48, 75ish, 100+ sets. Each of these sell for a charmingly outrageous price; out of the financial realm of any but grandmothers (who always seem to buy them for tikes incapable of full utilization) and syndicated cartoonists (who wouldn't purchase these anyways, prefering to have their inked drawings rendered in photoshop or gimp).
A large proportion of Graffiti writers who hit up blackbooks are loyal to this art-pen brand. The price of the product may be inflated due to the villanous zeal of the hordes of artists who steal pack upon pack of these lovely pens for use in their piece-planning and tag-scribble efforts.