A comparative study to test the efficacy of a novel device - the MiniBoxPFT, in measuring TLC (total lung capacity) compared to TLC measured by standard body plethysmography using the ZAN 500. The study will be conducted as a prospective two-arm, open, randomized comparative study.

This study is a prospective, multi-centered, randomized, comparative study designed to demonstrate substantially equivalence performance of the proposed device, the PulmOne MiniBoxPFT, to its predicate device, the ZAN500, for the measurement of total lung capacity (TLC).

Inclusion Criteria:

1. Subject is at least 18 years of age.

2. Subject is cooperative and capable of following instructions.

3. Healthy subjects:

   1. Never smokers.
   2. No known history of respiratory, cardiovascular, hepatic, renal or metabolic disease.
   3. BMI < 35.
   4. No persisting respiratory symptoms during the last 12 months. (e.g., dyspnea, chronic cough, wheezing or phlegm).
   5. No history suggesting upper respiratory infection during the three weeks prior to testing.

4. Patients with known disease affecting the respiratory system, with previous documentation of obstructive, restrictive, or mixed obstructive plus restrictive ventilatory abnormality.

Exclusion Criteria:

1. Subjects who are unable to satisfactorily perform routine, full lung function testing(due to non-compliance or claustrophobia).
2. Subjects unable or unwilling to give informed consent.
3. Subjects who have performed any significant physical activity during 1 hour prior to the Study.
4. Patients with a tracheostomy.
5. Pregnant women.