This is a Rectify Series drop-in speaker system for Bachmann Soundvalue SD70ACe locomotives. The speaker mounts in-place of the stock speaker in the fuel tank. No modifications are needed to replace the factory speaker.
If you want an even bigger, bolder sound, forgo the fuel-tank speaker and mount a UFIT-7240 speaker under the shell in the rear position and a UFIT-2120 just behind the cab. Wire these series for a 16Ω load to the stock Soundtraxx decoder. Secure the speakers with a strap of tape over the enclosures.
The speakers come fully assembled and tested.