The ESU 50343 is a repackaged Tang Band T1-1925S. It measures 14mmH x 29mmW x 65mmL (without the mounting tabs, which may be trimmed off). It is a 2W, 4Ω speaker and features a passive-radiator to extend the low-frequencies.  I do find the upper-mid and high-frequencies are a bit lacking in these, but otherwise these are great speakers if you have the available room and work well paired with a Boiler-Barker or another of my speakers to extend the overall frequency-response.
 
Since these are 4Ω speakers, you will need to wire them in series when paired with another speaker.