Two-Tone Counting Stones, Set of 20This inviting set of 20 double sided stones is ideal for counting, pattern making, number bonds and sorting activities. These durable two color counters, made from a unique stone mix, can be used both indoors and outside, and in water and sand. They are ideal for use alongside the 10 Frame Tray, which supports additional activities such as sequencing and an understanding of number bonds to 10. Contains 20 stones measuring 1. 75" across. Age 2+.