Here for sale is a 13x18mm High Quality Sugar Cube speaker. Overall dimensions with baffle is 15mm x 20mm x 6.5mm.
8 OHM 1 watt 384hz-20khz. I have tested dozens of small form factor speakers, and these are the best I have found. They are close in quality to 35x16 speakers, but once you buy the larger speaker + make/buy an enclosure, this smaller speaker is a good deal. Especially when ordering in quantity (see below).
The price is $10.00 including shipping.
Quantity Discount! If ordering quantities of 2 or more, use the "Make Offer" button and enter $9 each.
About the Sugar Cube Speakers:
These tiny speakers are the best! Some say they sound better than much larger speakers, and I would have to agree. I'm going to use them exclusively for my HO collection from now on. They are full-range speakers and are surprisingly loud for their size. They come with a baffle that I made. I ship them unassembled, assemble yourself and save!
Check out my store for other model railroad items, including more sugar cube speakers: