Check the listing for details. Barometer Electronic precision aneroid Mk1. Listed at 744.26 USD. Barometer Electronic precision aneroid Mk1. This would have been used by the military to set the altimeters on aeroplanes. The exact atmospheric pressure can be measured on the airfield. This could then be dialled into the altimeter on the aeroplane. A quite unusual and interesting version of these instruments. I would guess its made by Negretti and Zamba. Its fully working with the light diode in good order and bright.