As its name suggests, a chalk marker boasts the virtues of both. It marks with ink that resembles chalk but does not leave dust or break off in bits when you write on the blackboard. Also writes on plastic, metal, glass and other non-porous surfaces. Unlike other markers, the Securit chalk marker keeps its ink from drying out with a special valve system in its tip. The ink resists smudging and fading but wipes off clean with a moist cloth, leaving no trace on the board the way solid chalk does. The chalk marker in this set has an edge tip 2-6mm. The tags are 1/64 inch (1/2 mm) thick, size A7 (74mm x 105mm / 2-7/8 x 4-1/8 inch) and made of a flexible, finely textured nylon. They come in handy as place holders / reservations, table-number signs, name tags, prices and specials.