Diode Identification

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Mddeming-at-aol-dot-com>

Hi All,
       I recently acquired 2 diodes in a pile of stuff which are black
rectangular solids measuring 0.75" square by 5.50" long with both a solder
terminal and screw terminal at each end. There are no visible seams. The only
markings, aside from the diode symbol, are KVP-20 above the symbol and EDI-7934
below it. I assume that this means a 20KV PIV, but I have no other specs.
Anyone familiar with these, or got a guess on how to find the other data?
Matt D.