The W63 is a screened pentode and was designed for intermediate frequency amplifiers in superhet receivers. It is high impedance type allowing for a high Q in the tuned anode circuit. It is the M-OV implementation of the 6K7G design. The KTW63 superseded the W63.
The M-OV etched ellipse with the Type designation within identifies the origin.
The paper label brands this as an Osram consumer product.
The control grid is wound on copper supports for good heat transfer. All three grids extend outside the anode.
The anode and grids are circular in section. The bright circle near the base is a screening disc.
The classic envelope is 38 mm in diameter and, excluding the IO base pins the valve is 104 mm tall.
References: Data-sheet, 1040 & 1043. Type W63 was first introduced in 1937.