BPd-HD introduces clear, crisp, digital signals to plethysmography, eliminating the need for temperature equilibration, increasing patient comfort, and improving workflow. Performs spirometry, airway resistance, lung volumes (vtg), specific conductance and single breath diffusion. nSight software streamlines the testing process, SQL 2000 database, and USB data acquisition with the the First Digital plethysmograph providing crisp, clear waveforms and decreasing test times. 5-sided glass enclosure can be easily cleaned without clouding. The unique door assembly decreases the footprint and increases patient accessibility.