The CV475 is a Vari-μ sub-miniature pentode with flying leads. The prototype was the special quality 5899 and the normal commercial version is the EF731.
Written on the glass is what appears to be VX7507.
The anode is in two sections with a strap between. A glimpse of the grids is possible in the lower part of this image.
The flying leads sealed in the hard glass base disc.
The thin glass tube envelope is 10 mm in diameter, and excluding the B8D/F base wires is 38 mm tall.