I never saw one of these up close until a year ago and now a couple have shown up on ebay. It's a standard Simmon Bros. lens cone for a 135mm lens but with a plastic adapter that allows a Pacemaker lensboard to be attached, very similar to the Graphic View to Pacemaker adapter. I suppose it was marketed to the hobbyist that couldn't afford an enlarging lens or possibly it was used when converting the DII enlarger to a copy camera and you needed a shutter (or flash sync)

http://tinyurl.com/4lv6k7

or do a search on ebay for omega enlarger parts