IRWIN 4935524 Marking Chalk Refill, Indigo Blue, Permanent, 4 LB

Irwin STRAIT-LINE® Marking chalks have a newly engineered flip-top cap that keeps the chalk in the bottle where you want it and stops it from spilling out in areas that you don't. The flip-top cap, available on all Irwin STRAIT-LINE® chalk bottles, seals the chalk in an air-tight chamber, keeping out moisture and reducing the risk of clumping.