This is a Rectify Series drop-in speaker system designed to mount in what would be the cab area of most Athearn Genesis B-Units (the latest-run B-units have a redesigned frame these will not fit). I call this the B-Bomb (F-Bomb?), as it's large size really permits the low-frequencies to blossom. More than just a box, the enclosure features Diapasonic Tuning™, which allows the lower frequencies to accurately develop and resonate, clears the midrange of excess resonance and tunes the upper-mid/high response. The speaker features pins that mount into the cab interior holes and a touch of adhesive secures the system. No modifications are required. Use alone or together with the AHGS-F700-RC1 (pre-sound frame) or AHGS-F701-RC1 (sound-ready frame) for an even bigger sound!
If your B-unit has the holes where the cab-interior would mount, this should work. If your B-unit chassis looks to have circular recesses for speakers at both ends, it's likely the newer chassis that will not fit.
The speaker comes fully assembled and tested.
Dimensions are: 14mmH x 26mmW x 42mmL