Quick-adjust piano bench

[Jurgen Goering]

I have a music teacher who does a lot of group lessons and is tired of 
forever cranking the piano bench up and down for her little students.  
She is looking for a piano bench with the spring lever quick adjustment 
feature, the kind of mechanism found on some piano chairs (with backs) 
made in Japan or Europe.

Does anyone know of a source for benches with this kind of height 
adjustment mechanism?

Jurgen Goering
Piano Forte Supply