Cabin Pressurization Rate of Change Selector B-50 KC-97
This offer is for a vintage 1950s Cabin Pressurization Rate of Change Selector made by Airesearch, which appeared on the engineers panels of the US Air Force Boeing B-50 Bomber and KC-97 Stratotanker. It has two overhaul date stamps, 1969 and 1972. See photos of the diagram and descriptive text from the B-50 Flight Manual. Both measure 3.25in diameter and ~6in deep.