The CMG8A is a gas filled photocell and a variant of the CMG8. The CMG8 as specified in the document for CV1432 has black enamel on the glass except for the window. This photocell has clear glass. The operating voltage is marked on the box and with a sticker on the envelope itself.
The screw top cap is typical of early 1930s design practice.
The cathode is V shaped with an included angle of about 60 degrees. The anode is a square wire ring seen on the right of the cathode.
The caesium silver coated cathode. This device is new and has been kept dark in the box.
The wide glass tube envelope is 34 mm in diameter, and excluding the B4 base pins is 107 mm tall.