The LokSound by ESU Rectangular Speaker with Enclosure is ideal for use in model locomotives as a replacement for a 20 x 40mm speaker. With the help of the built-in passive radiator in conjunction with two rectangular speakers, the module achieves a significantly improved bass response and achieves a considerable sound pressure even at the high and mid-range. The module is particularly suitable for diesel or steam locomotives, where emphasis is placed on contemporary bass reproduction. This speaker includes a built-in enclosure to enhance its output and is rated at 4 Ohms. This rectangular speaker measures 7/8 x 1-21/32 x 5/16" 22 x 42 x 8mm.