Check the listing for details. Industrial Scribe and Engraving Pen - Wasp Pneumatic Tool. Condition: New. Listed at 324.95 USD. When it comes to free-hand decorative concrete engraving, touching up, removing islands, voids, and adding extra details to the engraved pattern, the Mini-Mochton Stylus Wasp Concrete Engraver is a handy pneumatic tool. The Wasp’s name comes from its design--it has a single reciprocating carbide stylus cutter, called a "Stinger". Air compressor required (1CFM at 90PSI) The Wasp can be used for fine details, touch-ups and free-hand work on a variety of surfaces: plastic, wood, glass, metal of all types, stone, concrete…the list goes on and on. Because of the single-stylus Stinger and the overall streamlined shape of the Wasp, it is easy to hold and work with. If you can use a pencil, you can use the Wasp. Stinger life depends on variables such as the amount of pressure exerted by the user, angle and depth of engraving, hardness of the surface, and lateral/sideways pressure. Used correctly, the Stinger will give you many hours of engraving. Replacement Stingers are available singly or in a six pack.