These are high quality US made prism devices to allow you to get more elevation out of your current scope set up.  Both are set up for picatinny rail mount and they mount in front of your existing optic.  These Micro Charlie devices are not adjustable and one is set for 20 Mils and the other is for 40 Mils.  They each come in their own hard case.  They are both brand new units and have never been used.  Purchased then quit doing ELR events.  For any extreme long range shooting these are a must.  The Micro Charlie is now only manufactured for the military.  This has been replaced by the Bravo version for civilian use and the Bravo's run about $900 new, so half price is a great deal.  Read more about them on their website www.tacomhq.com

Micro Charlie 20 Mils - $450
Micro Charlie 40 Mils - $450