Barometer, Aneroid, Demonstration Type

Instrument Similar To Cat. No. 1140100 In Construction, But Completely Enclosed In A Transparent Plastic Case With Movements Clearly Visible For The Demonstration Of Its Working With Resettable Index Pointer. Actual Effect Of Increasing Or Decreasing Pressure Can Be Observed As Air Pressure Is Changed By Squeezing And Releasing The Attached Pressure Air Bulb. (Barometer, Aneroid, Demonstration Type)