These are Rectify Series speaker systems for Kato RS-2/RSC-2 locomotives.
 
Three different systems are available:
 
The KATO-RS2L-RC1 replaces the long-hood weight and mounts to the frame with some double-sided mounting tape (you could also mount it in the shell). This speaker requires gluing an SMD-LED behind the stock headlight lens. You can use a Nix Trainz Decoder Buddy and 21-pin decoder, a Loksound Direct or a hard-wired decoder install. Soundtraxx PNP decoders are a bit too long with this speaker and will require using the KATO-RS2S-RC1 in this location.
 
The KATO-RS2S-RC1 replaces the short-hood weight and mounts to the frame with some double-sided mounting tape (you could also mount it in the shell). This speaker requires gluing an SMD-LED behind the stock headlight lens. Add this speaker to the KATO-RS2L speaker for a dual-speaker configuration, or use this speaker in the long-hood if you plan to use a Soundtraxx PNP decoder.
 
The KATO-RS2X-RC1 uses a touch of adhesive to mount inside the cab and cleanly fills the cab space with blacked-out windows. A small amount of the shell needs to be cut out below the cab. This is the speaker to use if you need to keep all of the factory weight in place and are willing to sacrifice a cab-interior.
 
The speakers come fully assembled and tested.
 
Dimensions are:
KATO-RS2S-RC1: 15mmH x 16mmW x 22mmL
KATO-RS2L-RC1: 15mmH x 18mmW x 32mmL
KATO-RS2X-RC1: 17mmH x 30mmW x 15mmL
 
VIDEO: https://youtu.be/RUztD7CBfwM