This Bowser - Stewart Speaker Enclosure is just the thing for adding sound in your Bowser, Atlas, Fox Valley and other diesels. Speaker enclosure comes with two 11x15mm, 8 Ohm impedance, sugar cube speakers installed with wire and plug. The speaker housing with speakers can be wired into many locos by cutting off the plug. The overall enclosure with speakers measures: 16.4 x 35.25 x 9.5mm and has four mounting holes for 2mm screws.