Crayola-Color Core Washable Sidewalk Chalk: Assorted Colors. Each chalk stick has a bright bold Crayola color core that makes cool double-colored shadow effects. When you are done, simply roll out the water hose to rinse it all away! This 4-1/4x4-1/4x7/8 inch package contains five color core chalk sticks. Recommended for ages 4 and up. WARNING: Choking Hazard- small parts. Not for children under 3 years. Non-toxic. Conforms to ASTM D 4236. Imported.