I played a 1928 National Triolian at a music store a few months ago and it had a greater sound than any of the other resonator guitars (both Dobro and National Resophonic) at the store, most of which were brand new. The finish of the instrument was in very poor condition, and the owner was willing to sell it for $2000. I can only imagine what a well-preserved one would sell for, if there is a well-preserved one left in the world.