These are Rectify Series drop-in speaker systems for Kato SD80/90MAc locomotives. There is a front-mount system and a rear-mount system. Choose one or the other or both for maximum impact! If choosing only one system, I recommend the front system as it is larger and will provide a bigger, deeper sound. The speakers use a touch of adhesive to mount to the frame. They feature integral rings to route the truck-wires through, keeping them clear of the drive-shaft. The design leaves plenty of room in the middle to mount any kind of decoder and/or motherboard you wish.
The speakers come fully assembled and tested.
Front-mount dimensions are: 12mmH x 18mmW x 39mmL
Rear-mount dimensions are: 10mmH x 14mmW x 23mmL