3 years & up. These tactile stones offer an engaging, multi-sensory way for young children to practice correct letter formation. Each stone is carefully engraved to provide important sensory feedback. Starting at the green dot children will enjoy tracing each letter shape with their finger - over and over again - building important motor-memory skills. The set contains 26 letter stones, 3 1/2 - 6 inches long, and an activity guide.