Universal open speaker housing for the TCS 20mm round speaker (included). This housing has limited use because of the open back however it can be useful in some situations. It can be useful for example for mounting the speaker on the underside of a coal load in the tender.  It should only be used in situations where the sound coming out of one side of the speaker is sealed and ported out of the loco shell or tender with holes drilled in the coal load and the tender or loco shell can act as the enclosure itself. In cases where the tender body itself is the speaker enclosure it can produce very pleasing sound.