Markal Pro-Ex Extruded Clay Based Crayon, 1/2" Hex, 4-5/8" Length, Black (Pack of 12) The clay-based "feel" that high-volume lumber crayon users prefer Stronger formula for reduced breakage Display packs have a convenient tear-off top to display the crayons for individual sales Measures 4-5/8" length by 1/2" hex Superior performance on wet wood; lead-free; extruded