The 580 series of oscilloscopes from Tektronix includes:
581 − 100 MHz single-timebase scope (1959)
581A − 100 MHz single-timebase scope (196x?)
581 − 100 MHz dual-timebase scope (1959)
RM585 − rack-mount 585
585A − 100 MHz dual-timebase scope (196x?)
RM585A − rack-mount 585A
They use 580-series plug-ins:
Type 80 − Single-input 100 MHz vertical plug-in for P80 probe (1959)
Type 81 − Adapter for 500-series Plugins (1960)
Type 82 − Dual-input 85 MHz amplifier (1962)
Type 84 − Calibration fixture (1962)
Type 86 − Single-input 85 MHz amplifier (1963)
