544
The Type 544 is a 50MHz scope with one timebase.
The 544 (at least the early ones) uses the same tunnel diode triggering circuit as is used in early 547 (tunnel diode in the collector load of a PNP differential amplifier).
A factory modification, MOD 108G, was available that increased the accelerating voltage to 24kv. The 1968 catalog lists an RM544 Mod 720 which has a direct-access plug-in and has 1ns risetime.
The vertical amplifier of the 544 is the same as the vertical amplifier of the 546 and 547.