[Amps] Russian HV Supply Capacitors

[radio at modesgate.com]

To the un-initiated, these look like an elegant solution to my HV
smoothing capacitor requirement.  Perhaps too elegant a solution.  Am I
missing something?  If anyone has an opinion, or direct experience of
using these, commentary would be appreciated.

http://www.ebay.com/itm/60uF-4kV-6kV-HIGH-VOLTAGE-CAPACITORS-New-Lot-of-2pcs-hv-plasma-laser-tesla-/201017069009?pt=US_Ham_Radio_Amplifiers&hash=item2ecd8d0dd1

If they are any good, any info on cheaper sources (or any for sale in the
UK) would also be good.

73

Denis MW0CBC / GW8OQV