This is a caesium-on-silver photocell. The CV number is written by hand. It carries the handwritten serial number 55237, with '35' and '72' being written, again by hand, either side of the broad arrow symbol. The voltage of this cell is marked as 80V.
Pin 2 is available as an additional anode connection if required - the EVS data suggests that manufacturers should bear this in mind.
This file was last modified10:52:52, Sunday August 07, 2016