How much is my Rangefinder worth?

I'm considering selling my old Laser Rangefinder, it's Russian military model LPR-01 ( very similar to Newcon LRB20000 ) It's used but working perfectly (need new battery, no problem to measure forest at 20000 meters !
The problem is, I don't know how much is worth, please suggest how much I can sell it for? Thanks.

You can do some research at gunsamerica.com or gunbroker.com. Shotgun News and Gun List may be of some help, also.

I've been looking for some time, but haven't found anything similar.
They're all made for "short" range (1200 to 1500 yards).
Picture of my 20km LRF : http://img185.imageshack.us/img185/8867/lrf.jpg
almost same as 10km SIMRAD LP-7:http://www.vinghog.no/vinghog/products/electro-optics/laser-rangefinder/le7/
and NEWCON LRB20000:http://www.newcon-optik.com/lrb20000a.html