Do-A-Dot Rainbow Marker Classroom SetNo cups, no brushes, no mess! This 18 piece classroom marker set consists of washable sponge tipped markers that make art time easier and cleaner, especially for little hands. Theyre washable, made with a special non clogging formula that won't dry out, even if the markers are left uncapped. Do A Dot Paint Markers are 5" long and contain 2. 5 oz (74 ml) of paint. Perfect artists ages 3 and up.