Yellow Door 22-Piece Number PebblesAppealing to children's natural instincts to sort and collect, these durable and tactile pebbles can be used in sand and water both inside and outdoors. Each pebble is cast from a special stone and resin mix and engraved and hand painted with a numeral making them highly appealing. Perfect to encourage children's fascination with numbers. Each set includes a leaflet full of ideas and activities.