The LokSound by ESU Rectangular Speaker with Enclosure is ideal for use in N, TT and small HO Scale model locomotives. This speaker includes a built-in enclosure to enhance its output and is rated at 8 Ohms and 5 Watts. At only 11/32 x 1/2 x 1/8" 9 x 13 x 3mm, this tiny speaker will easily fit inside widely used narrow-hood diesels such GPs, SDs, GE U-Boats or GEVO diesels as well as other locomotives.