There is a seller on eBay who has multiple units of an 18-plane core stack (Univac military surplus) that have not been chopped up for display. They are sealed in vapor-barrier bags. I bought one, and it appears to be a refurbed unit packaged for spares. Price is $295 "buy it now". Item # 180320226997 This is just one of them. Search for the other listings. --Bill