Featuring the Extreme Bold Snap line, the extra heavy-duty chalk box holds twice the amount of chalk compared to the Extra Bold snap line. It is ideal for field jobs where continuous snapping is required. Premium braided snap line creates Extreme Bold 0.07 in ( 1.8 mm ) lines Holds 2x more chalk than the Extra Bold Snap Line marking tools Heavy-duty aluminum case integrated with non-slip grip surface Large refill port also allows for convenient felt replacement Double-speed winding mechanism 50ft or 100ft Tajima Chalk-Rite Dura