This is an open-label, non-drug methodology trial in which subjects undergo a stepwise series of tests to evaluate their ability to use a mouthpiece to deliver nebulized therapy.

The trial consists of a screening assessment and familiarization session, and two nebulization assessments, conducted over two site visits. The screening assessment, familiarization session and first nebulization assessment will take place at Visit 1, while the second nebulization assessment will take place at Visit 2. The total duration between Visits 1 and 2 will be 4 - 8 days. Each visit is expected to last up to 2 hours.

At the initial visit (Visit 1), eligible subjects (i.e., children) and their parent(s)/legal guardian(s) will be approached to ascertain their interest in trial participation. Interested subjects and their parent(s)/legal guardian(s) will proceed to a nebulizer familiarization session. After informed consent has been obtained from the subject's parent(s)/legal guardian(s), the subject will proceed to Nebulization Assessment 1.

At Nebulization Assessment 1 (Visit 1), all subjects will perform 3 attempts of 19 inhalations, each inhalation of 3 seconds duration. Nebulization Assessment 2 (Visit 2) will occur 4-8 days after Visit 1. Subjects, who failed to achieve nebulization success at Attempt 3 during Visit 1, will perform 3 attempts of 28 inhalations, each inhalation of 2 seconds duration at Visit 2. Subjects, who achieved nebulization success at Attempt 3 during Visit 1, will perform 3 attempts of 14 inhalations, each inhalation of 4 seconds duration at Visit 2.

At each visit, Attempts 1 and 2 will be made with air only. Attempt 3 will be made with isotonic saline (0.9% NaCl). Nebulization success will be assessed at Attempt 3.

Inclusion Criteria:

• Male or female subjects aged 1 to <5 years
• History of coughing and/or recurrent wheezing within the last year, otherwise healthy
• Use of an inhaler with a spacer or nebulizer for at least 30 days (consecutive or otherwise) within the last year. Examples of inhaled or nebulized therapy include the use of a regular controller (inhaled corticosteroids (ICS) or ICS/long-acting beta-agonists), or a reliever therapy (e.g., albuterol) on an as needed basis for the relief of symptoms
• Written informed consent from the subjects's parent(s)/legal guardian(s), including privacy authorization, prior to trial participation
• Subject's parent(s)/legal guardian(s) must be willing and able to comply with the trial procedures and visit schedules

Exclusion Criteria:

Screening (Visit 1)

• Any significant medical conditions (apart from a history of coughing and/or recurrent wheezing) that in the opinion of the investigator would interfere with the subject's ability to use the mouthpiece and/or follow the protocol procedures
• Subjects with current respiratory symptoms or breathing difficulties at the time of screening
• History of paradoxical bronchospasm or hyper-responsiveness following inhaled therapy that in the opinion of investigator may put the subject at risk when inhaling isotonic saline
• Parent(s)/legal guardian(s) who is an employee of the investigational site or the Sponsor, who is directly involved in the trial, or a family member of such a person

Nebulization Assessment 2 (Visit 2)

• Development of any new illness or condition between the Screening (Visit 1) and prior to Nebulization Assessment 2 (Visit 2) that in the opinion of the investigator would interfere with the subject's ability to use the mouthpiece and/or follow the protocol procedures
• Any safety concerns that in the opinion of the investigator would jeopardize the subject by his/her continued participation in the trial