This filter is about a year old; I bought it and then we moved to a fairly dark-sky site less than two months later, and the filter is no longer needed. Worked very well in my previous urban (mag 3.5-4) skies for CCD imaging. This is the 2" filter that you can thread into the face of most CCD cameras, camera lenses, and 2" nosepieces.
Asking $155, shipping included (UPS ground). Will send the test results with the filter; I still have all the original paperwork.