This is a Rectify Series drop-in speaker system for Atlas Master U28C locomotives. The speaker uses double-sided mounting-tape to secure to the chassis. No modifications are needed to replace the factory speaker. Use the stock speaker wires or purchase the large 2-pin speaker harness from the "Parts" page.
 
NOTE: one customer has told me that his U28C uses a wired 3mm LED to light the rear light package. If your U28C has this and you want to use the stock 3mm LED, you may be better off buying the Atlas Universal #1 "deck-mount" speaker: https://www.scalesoundsystems.com/product-page/atlas-master-u23-30-33-36b-b23-30-7
 
The speaker comes fully assembled and tested.
 
Dimensions are: 9mmH x 17mmW x 40mmL
 
Video: https://youtu.be/yzvxmBmIftQ