200 hours would be ideal although they sound very special by 100 hours for sure. I'm a hugh advocate of the Duelund CAST. After all these years of having them in my speaker's tweeter site and in my DAC (output coupling capacitors) I thoroughly appreciate their sonic impact in my system. They're a tremendous high quality product that I'd recommend wholeheartedly and without reservation. Worth every cent! Thanks Bill (Grannyring) for the recommendation years ago.
Charles
Charles