I have no way of knowing if the gauge works or how accurate it may be. Approximately 11 inches in diameter, including wood case.The item “ABSOLUTE PRESSURE-MILLIMETERS OF MERCURY-WALLACE&TIERNAN” is in sale since Sunday, October 05, 2014. This item is in the category “Collectibles\Science & Medicine (1930-Now)\Scientific Instruments\Other”. The seller is “woodenworks” and is located [...]