SoundTraxx 35 X 20mm Oval Speaker
 
If you have more space, this speaker is great for larger models.
 
Dimensions: 35 x 20 x 5.3mm(D)
Frequency Response: 560Hz - 20kHz
Power: 1 Watt (Nominal) 2 Watts (Peak)
Impedance: 8 Ohms
 
MSRP; $15.95