This is a Rectify Series drop-in speaker system for Atlas Master (current-run) GP38/40 locomotives. 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 uses a touch of adhesive to mount and no modifications are needed to replace the factory speaker.
 
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