These are Rectify Series drop-in speaker systems for Bowser Executive RS3 locomotives. Two versions are available:
 
The BOWS-RS3S-RC1 speaker is identical in size to the stock speaker and uses the factory mounting screws. No modifications are needed to replace the factory speaker.
 
The BOWS-RS3L-RC1 speaker is a longer version and is secured with a strap of tape over the top. It provides a little deeper sound. No modifications are needed to replace the factory speaker.
 
If you're a fan of dual-speaker configurations, you can nip the mounting ears off of the BOWS-RS3S speaker and it will nicely fit on the chassis under the short-hood with a strap of tape. You can then use the BOWS-RS3L in the stock position under the long-hood. A TCS KA2 nestles nicely behind the control stand if desired.
 
You may need a 2-pin wiring harness to connect the speaker to the PCB. Bowser now uses TWO different sizes of these on the RS3s. Please see the third set of photos to see the difference in circuit boards. You can choose what size of harness you need based on how your circuit board looks. You will either need the Medium 1.25mm size or the Micro 0.8mm size. You can find these in the PARTS section: https://www.scalesoundsystems.com/parts
 
The speakers come fully assembled and tested.
 
Dimensions are:
BOWS-RS3S: 7mmH x 17mmW x 25.5mmL
BOWS-RS3L: 7mmH x 17mmW x 35mmL
 
VIDEO: https://youtu.be/uCZTq1rbbfs