Duende vs Halo Tube Rings

I would like to get input from users as to their preference.Pros/Cons.Which are better for certian applications IE: Output,Driver,Input Tubes.
I would suggest finding some common O-rings.
Read about O-rings in the Wiipedia.
They can be found in all sorts of materials and even some exotic cross sections.
Get some perflouroelastomer rings (the raw material costs thousands of US$ per kilo!!!!)
Personally I would just buy any.. and stop wondering that I did not get just the right ones. (as if...)
I have to agree with Elizabeth on this one, it's worth trying the inexpensive solution first. I got 50 industrial grade silicone o-rings from here:


for $10 plus shipping. I had a preamp with all octal tubes, so the S1000-216 o-rings were the perfect size. Now I have a preamp with 9-pin miniature tubes, so the S1000-211 are the ticket. I use 2 per tube, and they make a noticeable difference in microphonics. Would Herbie's or one of the other far more expensive dampers be better? Maybe, but I'm not sure my rig has enough resolution to prove it. I'm happy with my cheap o-rings.

Plus, you can get them in about 10 different colors to match your decor. :-)

Most O-rings are Buna-N, also called nitrile rubber. These won't take the heat. Viton fluoroelastomer is much better at the heat, up to 400°F, and silicone to 450°F.

I bought a used TAD-60 tube amp that came with Herbie's tube dampers. They appear to be very good quality, but make no audio difference on this rig. The designer of the amp, Paul Grzybek, suggested that if a fingernail tap on the tube creates a sound from the system, try dampers--this unit doesn't.