What makes a good equipment rack?

didn’t those Zoethecus platforms originally use Sorbothane for the viscoelastic material

The heart of the Zoethecus system is the Z Slab. The hand-laid composite core consists of 10 discrete sub-layers of phenolic, viscous damping fluid, aluminum and high density fiberboard to thoroughly dissipate component resonance. This top-of-the-line 15-pound slab is perfect for heavy amps, transports and turntables.

I don’t have any experience with SRA products but you have to hand it to their marketing dept.

From their page for Virginia Class iso stand,

“Each jewel-like chassis features a custom-made nanocomposite housing. This creates the ideal coupling path between component footer and isoBASE, enabling it to drain and sink skin-effect vibration.

Under this nanocomposite skin are two of our enormously complex Raft Isolation Systems™. Each is encased in its own vacuum and calibrated to single-angstrom tolerances. It’s our most reactionary, most effective implementation ever.

Mechanically grounding this to your floor are build-specific leg assemblies. These are made of HY80 high-tensile steel, a material originally developed for the hulls of U.S. nuclear submarines.”