The Tektronix Type 50 is a vertical plug-in for 560-series scopes.
It was introduced in 1961. It is an AC amplifier with a frequency response of 15 Hz to 200 kHz. It provides a fixed 1 mV/div sensitivity. The only control is vertical position. When paired with a Type 51 sweep, the Type 50 is useful for measurements in the audio frequency range.
The Type 50 has a pair of 2N1631 germanium PNP transistors driving an output stage comprising a differential pair of pentodes.