These are drop-in speakers for Athearn Genesis U50 locomotives. These do not fit the Athearn RTR U50s, which are found here: https://www.scalesoundsystems.com/product-page/athearn-rtr-u50-rear
 
Two options are available:
 
The AHGS-U50S speakers replace the stock speakers/weights and simply screw-in like stock. There will be about 2.6 ounces of weight-loss doing this but the model still weighs a whopping 1 lbs. 13 oz. without the stock weights. There is a large areas behind the rear speaker where you can add weight to makeup for the loss if desired.
 
The AHGS-U50B speakers replace the front and rear blower details. This lets you retain the stock weights but the see-through screens and blower detail will be blacked-out by the speakers. Simply use some thin mounting-tape to secure these speakers in place of the blower details.
 
A third option uses the AHGS-U50S in the front position and an AHGS-U50B in the rear position. This retains the front see-through screens and blower detail and the much larger rear speaker/weight, resulting in only 0.6 ounces of weight-loss.
 
The speakers come assembled and tested.
 
Dimensions:
AHGS-U50S-RC1: 14mmH x 18mmW x 40mmL
AHGS-U50B-RC1: 24mmH x 18mmW x 30mm