The Tektronix Type 63 was introduced in 1961. It is a 300 kHz differential amplifier with calibrated sensitivities from 1 mV/div to 20 V/div. The common mode rejection ratio is 50:1. At serial number 1320, the Tektronix Type 63 was renamed the 2A63. The 2A63 documentation applies to the 63.