The 415 is an adaptation of the HL-422 cabinet. This model has both stationary and rotary channels an it is intended for use with most 2 channel organs, through the appropriate connector kit.
The HL-422 was originally sold only with B3000 organs and has coners that match the B3000 cabinet. The 415 is the same as the HL-422 electronically, but it’s cabinet styling is more like a “traditional” Leslie design.