super zoom lenses for Nikon

I am selling tow super-zoom
lenses, I got both for a trip that has been cancelled and now I need to
invest their value in lenses that I will be using more! both lenses are
just tested never been used in field. Both for Nikon :)

    
1- Sigma (for Nikon) 150-500 auto-focus with Optical Stabilizer motor +
Sigma 86mm UV filter + original case, strap and manual, asking 900$

• For more info: http://www.sigmaphoto.com/shop/150-500mm-f5-63-apo-dg-os-hsm-sigma
• For more reviews and price :
  http://www.amazon.com/Sigma-150-500mm-Telephoto-Digital-Cameras/dp/B001542X64/ref=sr_1_1?ie=UTF8&qid=1315727576&sr=8-1

     2- Rokinon (for Nikon)  650-1300 manual focus + 2X converter with case, asking 170$

• http://www.amazon.com/Phoenix-650-1300mm-Telephoto-Teleconverter-650-2600mm/dp/B0034JOM7Q/ref=sr_1_5?s=electronics&ie=UTF8&qid=1315728210&sr=1-5