 Reversibility FEV1 Test will be performed at the Screening Visit. Within 30 min after the Screening Baseline FEV1 is obtained, the subject will self-administer 180 to 360 mcg Ventolin-HFA 2-4 inhalations. To qualify for the study, the subject needs to demonstrate an FEV1 reversibility of greater than or equal to 12.0, from the same-day Screening Baseline FEV1, with 3 to 8 attempts, at 30 min after inhaling Ventolin-HFA. Reversibility is defined as: 