Model M-1 in original leather case. Range is -1000 to +5000 feet. Shows some wear and scratching from age. Rear side has some scratching and deteriorating foam. Overall nice piece though. Let me know if you have any questions. The item “American Paulin System Micro Altimeter M1 Surveying Instrument W Leather Case” is in sale since Saturday, March 05, 2016. This item is in the category “Antiques\Science & Medicine (Pre-1930)\Scientific Instruments\Barometers”. The seller is “tyler_and_valerie” and is located in Fayetteville, Arkansas. This item can be shipped to United States.