dc10audio use Duelund CAST capacitor ?

Why are this any better than Mundorf sliver / gold ?? and why so expensive to buy?
still no way they are worth it how can capacitor in silver be 5,000 ? silver is cheap to buy?
Materials are only one cost. I am sure that Duelund is not selling in large volume, so the lucky few will have to bear that expense. From the reviews that I have read, I wish that I was among the lucky few.
The silver foil CAST capacitors are uber priced.The copper foil version,merely expensive.The copper CAST are well worth their cost given the very high return in sound quality IMO.One of the best audio puchases Ive made.