The drop-in speaker for Rapido M420 and M420B locomotives uses the UFIT-6730 speaker. The speaker uses a strap of tape to secure and no modifications are needed to replace the factory speaker. Please see the third photo for installation instructions.
 
The M420B has space to add a second speaker in the cab area using the BOWS-RS3S speaker taped to the underside of the PCB. You will nip the mounting ears off of the BOWS-RS3S speaker before sticking it in place. The low-nose M420 does not have room for this second speaker.
 
The speaker comes fully assembled and tested.
 
Dimensions: 7mmH x 16mmW x 30mmL
 
VIDEO: https://youtu.be/iHRBij5defg