These are Rectify Series drop-in speaker systems for Bowser Executive Line U25B locomotives. The speaker uses the factory mounting screws and no modifications are needed to replace the factory speaker.
 
THREE VERSIONS AVAILABLE
 
The BOWS-U25E is for the "early-run" models (that were probably never available with sound). The speaker mounts to the large posts holding the rear headlight (which will be removed).
 
The BOWS-U25M is for the "mid-run" models (most of which had an 8pin PCB). This version uses the BOWS-UNI2 speaker which screws into the four holes using a standard 16x35mm speaker size.
 
The BOWS-U25L is for the current-run models that have a speaker mounted with only two screws behind the decoder/PCB.
 
Depending on your decoder installation, a UFIT-Micro can often be placed behind the cab for a dual-speaker configuration. You'll need to measure space for this and select the speaker that best fits: https://www.scalesoundsystems.com/product-page/universal-micro-range
 
The speakers come fully assembled and tested.
 
Dimensions
BOWS-U25E: 15mmH x 18mmW x 36mmL
BOWS-U25M: 12.5mmH x 16mmW x 35mmL
BOWS-U25L: 17mmH x 18mmW x 35mmL
 
VIDEO: https://youtu.be/XtS_VIhB6FY