Rater of Climb / Vertical Speed Indicator, Pre-WWII

This is an early Pre-WWII-era Rate of Climb / Vertical Speed Indicator, measuring climb or descent up to 2,000 ft per minute. Made by Pioneer, part number 321-1177.

At 2.75 inches diameter, the face is smaller than WWII-era indicators. It is ~3.5 inches deep.  The glass is clear and the markings are superb.