This is perhaps the best known of the Leslie models, introduced in 1964 it replaced the single speed 22H and became *the* cabinet for use with the Hammond B3 organ.
While the amplifier is essentially the same as the earlier 22H, the 122 replaced the 22H and introduced 2 speed operation (Tremolo and Chorale).
This model was made specifically for the balanced output of a Hammond “G-G” Console (IE Model B3 or C3).