This is Vertex's recreation of the Dumble Overdrive Special. There's a sweet touch-sensitivity, rich complex harmonics, super clear note separation... it sounds great. 

Model: Vertex Ultraphonix HRM
Made: USA, recent model
Type: overdrive, Dumble voicing
Power: standard 9v negative supply (not included)
Equivalent new street price (approx): $319aud
Mods: none
Accessories: original box and docs
Condition notes: used, no major marks, excellent condition