1K9008.00011 - Dryer Danfoss C102 with spacer.
Call Phoenix Mobile Air, let them know it's for a Kerstner AC unit, and make SURE they confirm the new dryer has a pressure switch. There was some mix up when I made the purchase awhile back.
All that said, I'd be very careful about throwing too much money at the German "meat cooler". If I had focused my funds and energy towards a modern, common unit like the Dometic or Mach 8, I would be much more confident and happy with the cooling situation these days, I believe.