Applicable for green and wed wood, lumber and plywood, structural framing and masonry, marking metals in steel mills and lab shops, and much more. Extruded, day-based formula provides extended write out, superior strength, water resistance, fade resistance, smear resistance and unsurpassed color visibility. Saves on Inventory costs for special lumber crayons for special applications. Pro-EX does It all. Eliminates the need for "soft" style lumber crayons. Pro-EX is ideal for marking on wet, frozen or treated wood. Eliminates the need for special "graphite" black lumbar crayons. Use standard Pro-EX black Instead of graphite for higher temperature applications. Pro-EX is now available in 10 high visibility, high performing colors to meet all your marking needs no matter what the surface or application. Standard 1/2" hex shape fits the #109 peterson holder, #106 holder and #108 holder. Marking range: -20 degree F to 130 degree F (-29 degree C to 24 degree C). Available in yellow color.