This rare gem was obtained from Ebay. It's a Simpson, Model 880 AC watt meter. More difficult than finding this piece, are the wiring instructions. After hours of research, a copy of the original manual was obtained from Simpson Company. Believe it, or not, neither the meter, or the manual appears anywhere on the internet. Here is a picture of the meter and a FREE PDF of the manual. Yours to download and print, compliments of kjq.us.com.