The KT45 is rated as an audio output device with over 7 Watts output from a single stage. But the peak anode voltage is rated at 8,000 Volts. This clearly marks it out for duty as a line output stage in television type applications and indeed this was its intended use. The maximum anode dissipation is 21.5 Watts.
The KT45 appears to be a re-issue of the pre-war KT44 and has identical ratings but a different construction.
The paper label branding this M-OV made valve as an Osram consumer product.
The inner grids pass flat across the cathode. The control grid can be seen to be held within notches on the copper support rods.
The working face has the cooling flange at the centre. Note the ceramic insulators and cooling fins on the top of the control grid supports.
The classic envelope is 50 mm in diameter and, excluding the B7 base pins, is 123 mm tall.
References: 1043. Type KT45 was first introduced in 1947.