I bought my used 3458A ref board on eBay about 5 years ago from a seller in CO. It is the genuine article. I can't see how or why anyone would bother to make a really good fake board (complete with Vishay metal foil resistors) with a fake LTZ 1000A and sell it for $99.... If these boards were coming from China, maybe... Sent from my iPad Snip////// > On Sep 14, 2015, at 4:58 PM, volt-nuts-request@febo.com wrote: > >> On 14/09/2015 12:08, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: >>> On 13 Sep 2015 09:15, "M K" <m1k3k1@hotmail.com> wrote: >>> There has been some of those references available second hand from ebay, >> mostly pulled, but some may be counterfeit, so look for sellers with >> pictures showing it as old.. >> > Nick Gilbert wrote: > FWIW-I recently contacted a seller of 3458A ref boards asking how/where he was able to get them. He claims that he received many as NOS from a closed assembly plant-you folks would know better than I if that story holds water. He also says that many are purchased when folks upgrade to the 4ppm option. > > I would agree that any of the $99USD are likely fake. //////snip