Negretti & Zambra Pocket Barometer & Altimeter. London 25415 (on face). In working condition, (passed the plastic bag test). Brass case measures 1 3/4 ” diameter and 9/16″ deep. Barometric scale from 20-31 inches. Measures to 10,000 feet. Altimeter scale is calibrated by rotating the knurled knob at the top. [...]