The Spirometer is an excellent complement to the Horn and Bubble Hierarchies (which target abdominal grading and controlled oral airflow). It does not produce sound, so it is excellent for use with those who exhibit auditory defensiveness. It also features a dial which allows you to adjust the level of difficulty. Includes two mouthpieces (one flat, one round), and one nose clip. The Spirometer is especially useful for clients with VPI and children who need visual cues. The Spirometer helps build intraoral pressure and controlled airflow for adults, as well as for children, which translates into longer utterances, increased breath support, and coordination of tongue retraction with an open mouth posture required for vowel sounds.