In an attempt to mount a MTB and ride with a little damage to my back as possible, I seek a shock-absorber seatpost. 

I would like to borrow it first, and possibly buy it later, if for sale.

Beggars cannot be choosers, but I will try.  I am seeking higher quality posts, otherwise the test/purchase will be in vein.

Please let me know if you have one available.

Thank you.

mk