The Boiler-Barkers are a range of cylindircal systems designed to fit in HO smoke-boxes and boilers. Like all of my systems, extensive testing and listening was performed on dozens of components, culminating in a speaker system that produces a robust chuff with clear whistle and bell sounds. Use them alone or combine them with a tender-mounted speaker.
 
Fifteen systems are available in diameters of 13mm, 15mm, 17mm, 19mm and 21mm in three lengths of 15mm, 20mm and 25mm.
 
STBB-1315: 13mmDia x 15mmL x 10.5mmH
STBB-1320: 13mmDia x 20mmL x 10.5mmH
STBB-1325: 13mmDia x 25mmL x 10.5mmH
 
STBB-1515: 15mmDia x 15mmL x 12.5mmH
STBB-1520: 15mmDia x 20mmL x 12.5mmH
STBB-1525: 15mmDia x 25mmL x 12.5mmH
 
STBB-1715: 17mmDia x 15mmL x 14.5mmH
STBB-1720: 17mmDia x 20mmL x 14.5mmH
STBB-1725: 17mmDia x 25mmL x 14.5mmH
 
STBB-1915: 19mmDia x 15mmL x 17.5mmH
STBB-1920: 19mmDia x 20mmL x 17.5mmH
STBB-1925: 19mmDia x 25mmL x 17.5mmH
 
STBB-2115: 21mmDia x 15mmL x 19.5mmH
STBB-2120: 21mmDia x 20mmL x 21mmH
STBB-2125: 21mmDia x 25mmL x 21mmH
 
If used in conjunction with a tender-mounted speaker, be sure to know that speaker's impedence and wire accordingly. Soundtraxx and TCS are best suited with 8-16Ω speaker loads, while LokSound is happy with 4-8Ω speaker loads. Shown is a series-wiring diagram using a 4Ω tender-mounted speaker along with a Steam-Tweeter or Boiler-Barker.
 
These are 8Ω, 1W systems and come fully assembled and tested.