Two sets of three RollerBlocks--polished aluminum "cups" with ball bearings--used for component and speaker isolation. These are the Level 3-7075 RollerBlocks made by Ingress Engineering Products in Canada.

These worked very, very well under the Yggy DAC, Ayre Pre and Ayre Amp in my system. It made me realize just how essential vibration control/management is to great sound. 

Each cup contains small markings from use but I cannot see that they change ball-bearing movement.

Price new now for these on Ingress's site is $199 CAD--$158 US per set.  Asking $90 for each set of 3 RollerBlocks, $170 for both sets if purchased at once.

Prefer PayPal and will not ship other than to US addresses.