This is a Rectify Series drop-in speaker system for Rapido GMD-1 locomotives. The speaker uses a bit of tape or adhesive to secure and no modifications are needed to replace the factory speaker.
 
The speaker comes fully assembled and tested.
 
Dimensions are 7mmH x 16mmW x 45mmL
 
VIDEO: https://youtu.be/2l2vszODzOY