The CV4050 is a high reliability special quality RF pentode on a flying lead base and is for operation up to 400 MHz. The basic design is from the 5654/6AK5W and when fitted on a B7G base it is the CV4010. The 5654 is equal to the Mullard M8100 special quality version of the EF95.
The anode is open at the ends and the three wire grids can be seen within.
The bright plates above the top mica are screens connected to the cathode.
The thin glass tube envelope is 18 mm in diameter and, excluding the flying leads, is 37 mm tall.
Reference: Datasheet. Type CV4050 was first introduced in 1954.