These are Rectify Series drop-in speaker systems for Athearn RTR RS-3 locomotives.
 
TWO VERSIONS AVAILABLE:
 
For early, pre-sound versions, the speaker replaces the plastic tray in the long hood and no modifications are needed to install it. Shown is a mock-up of the speaker installed with a Tsunami2 PNP board placed over the motor. The top PCB mounts may need to be slightly filed down for a board like this to fit correctly (some claim installing the PNP upside down works better). A small hardwired decoder should pose no fit problems.
 
For current-run sound-ready or sound-equipped models, the speaker screws to the chassis in place of the stock speaker. I trimmed flush the un-used plastic clips behind the stock speaker on the plastic tray. No other modifications are required to replace or install this speaker.
 
The speakers come fully assembled and tested.
 
Dimensions:
AHRR-RS3X (early, pre-sound): 8.5mmH x 18mmW x 40mmL
AHRR-RS3S (current, sound-equipped/ready): 8mmH x 18mmW x 28mmL