Measurements: FEV1, FVC, PEF Display: Custom LCD Resolution: 10ml Accuracy: ±2% Volume range: 0.1 to 10 liters B.T.P.S. Flow range: 0.1 to 12 liters/second B.T.P.S. Keyboard: 5 Keys: On, Enter, UP, Down and Delete Interface: RS232 input/output 4800 Baud rate Memory: Up to 3000 spirometry results Power supply: Main Battery - 9v pp3 (typical life 3 months) Memory Battery - Embedded lithium cell (typical life 7 Years Dimensions: 6.5" x 2.5" x 2" Weight: 8 oz Software: Windows® compatible