Markal UltraScan Lumber Grading Crayons | Box of 12 Markal $49.30 Markal UltraScan Fluorescent Lumber Grading Crayons Tested to meet specifications for the Lucidyne ColorScan and Newnes-McGehee Mark Readers! Markal UltraScan Grading Crayons can be used on wet and green lumber and provide the highest fluorescent... Choose Options