Strait-Line, 5 LB, White, Chalk Refill, High Visibility Chalk For Self-Chalking, For Use On A Variety Of Surfaces Including Wood, Drywall, Concrete, Stone & Metal, Permanent Colors, Especially Black & Red, Produce Long Lasting Lines That Won't Fade, Temporary Colors, Especially White & Blue, Provide High Visibility & Are Easy To Remove, Proprietary Formulations For Dark, Sharp Lines & Reliable Performance, Chalk Containers Are Filled By Weight Not Volume.