Beautiful lens assembly with coated optics made in Japan by Kowa for Compugraphic. Compugraphic part #56636. We think these were designed to be used with optical comparators or photo typesetting machines. If you've got one then this is a great bargain. If not, take it apart for the optics. Has a 3 mounting hole flange and is 5 1/4" long with a 1" diameter barrel.