The Tektronix Type 544 is a 50 MHz scope introduced in 1964.
It has one timebase with several horizontal magnifier modes (×2, ×5, ×10, ×20, ×50, and ×100). To make horizontal magnification usable, the 544 has a vernier horizontal position control in addition to the regular horizontal position control. The fastest calibrated sweep is 10 ns/div. Some magnification modes provide sweeps faster than 10 ns/div, but in those modes the horizontal scale is not calibrated, and a lamp on the front panel lights up to remind the operator of that.
There is also a rackmount version, the RM544.
A factory modification, MOD 108G, was available that increased the accelerating voltage to 24 kV. The 1968 catalog lists an RM544 Mod 720 which has a direct-access plug-in and has 1 ns risetime (equiv. 350 MHz).