The 53CG is a gas filled photocell.
Our literature does not have a datasheet for this device as yet.
The top of the envelope reveals the electrode structure.
The thin glass tube envelope is 16 mm in diameter and, excluding the special base pins, is 37 mm tall.
Updated January 03, 2013. shape:thin.glass.tube construction:pinch type:photocell base: pins:3 pin: