These are drop-in speakers for early, pre-sound Athearn Genesis SD70, SD75M and other 6-axle models that use a smilar chassis. A UFIT-1245 sits on the rear "platform" while an SXTH-UNI3 with the mounting-tabs nipped-off sits on the front "platform". This leaves plenty of room in the middle for a Direct/PNP style decoder or a 21-pin motherboard.
 
The speakers come fully assembled and tested.