Here is a rare very large Datum 9520 digital Nixie Tube clock. The size is a standard 19" rack mount width, 10" in depth and 7" in height. Nixie tube numerals are about2" high Clock works great but is unsettable. You have to start it at 00:00:01. I can find no way to set it. It is a secondary clock so evidently the setting capacity lies in another clock. Franklly if I could set it I wouldn't sell it. Of course you can start it a 00:00:01 manually and it shows the correct 24 hour time. I do not have the power plug, I am running it with 2 alligator clips. Takes a smaller than normal 3 pin plug. I heard that they might be available at Radio Shack but haven't checked.. No dead nixies as far as I can see...but then I have not watched it every hour for 24 hours but I have yet to see one not function correctly. Due to possible shipping damage I am selling the clock as is but it seems to be 100% functional now. Buyer to pay $20.00 for S&H.