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.
Thank you for the info one more question if i order the instrument it comes with copper CAST but i want silver wire upgrade so silver foil makes sense but not for 5K extra is copper foil Cast OK with silver wire? Do cast copper sounds better than silver foil?
Each capacitor is hand built and sold in very small quantities.

I have been very lucky and have been privy to capacitor comparisons done at a speaker maker I know. He has 4 levels in his speakers - Erse - Erse bypassed with Duelund VSF Copper - VSF Copper and Cast. You can easily hear the difference with each level - its an increase in speed, clarity and naturalness.

I heard comparisons of two speakers both exactly the same except one used Mundorf SIO and the other Duelund VSF Copper. I listened to Patti Smith - Gloria with the Mundorf's - her voice was low, arresting and guttural - you go wow - but it did not sound like a normal female voice. Then the Duelund - it was not as arresting or as guttural, it sounded more recessed, you think its not as good as the Mundorf - but you notice its more natural and faster - things sound more life like. You go back to the Mundorf and you realize its false.

Forget the Silver - its a personal preference thing - some love Silver others like me don't like it - unless you really love what Silver does save your money and get copper. The speaker maker I know has checked it all out and doesn't even offer silver as an option - if you asked him he would build you one as a special order but at a much greater cost and you may not even like it - many, possibly even most, don't.

Regarding cost the Cast version of the speaker the manufacturer I know costs $13.5k. Expensive - yes - but there are many many much more expensive speakers out there. Personally I have not heard a speaker even close to that speaker regardless of cost.