Altimeter, Sensitive, PZL
This is a Sensitive Altimeter labeled for use in aircraft of Poland's PZL-Państwowe Zakłady Lotnicze (State Aviation Works). PZL is embossed on the dial of the instrument, although not readily visible in the photos.
Not much is known about this altimeter, other than what might be surmised from its service label from Palma S.A. Geneva dated 1962.
The bottom right mount has been modified/removed for an unknown reason.