CAUTION: AF-Confirm Nikon Adapter for EOS cameras

I bought one of these and it killed my Canon EOS 20D! If you are thinking about getting a AF confirming adapter, please read this before you decide one way or the other. The idea of a AF confirmation from the finder in the APS sized sensor Canon cameras is very tempting since the focus screen is not very large or bright, and when using Nikkor or other manual focus lenses, it may be difficult to be sure of really sharp focus. However, when I attached the device to my Nikkor lens and put it on the Canon camera, the battery showed as low power, then Error 99. This was followed by shorting out the circuits so the camera would not turn on, period. The Canon approved repair facility confirmed that the electronics in the lens mount and the main board of the 20D were damaged and needed to be replaced (ca $350). It is clear that the adapter did this. I had, before testing the Nikon to EOS AF mount bought a similar M42