Here is the one I use. http://cgi.ebay.com/UL-Certified-Medium-20-Plate-SS304-Heat-Exchanger_W0QQitemZ230413481613QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item35a5b6b68d
Although only a 20 plate, its extended length doubles the cooling capacity, giving more bang for the buck. the drawback was...