A set of 8 large stones designed to enable children to have sensory experiences by experimenting with the raised and indented shapes and patterns. Cast from a durable mix including real stone , they can be used on their own or for emaple, making imprints in play dough or sand. Activity guide included. Stones have four raised or bumpy designs (circles, dots, wavy lines and a grid) and four indented or hollow designs (circles, lines, zigzags and a spiral). Comes in a handy storage jar. Each stone measures 75mm.