I have the old Solid Steel’s myself, ozzy, Model 48. All they are is nicely made, somewhat lightweight (in comparison with the bulkier Sound Anchor) tubular metal frames (sand fillable) with MDF shelves, each shelf supported on three aluminum "isolation" cones. I put isolation in quotes because cones and spikes, though touted as providing isolation (decoupling), actually don’t; they couple. Put a piece on cones and move the shelf under it---the piece moves with the shelf. The tighter the coupling, the less the isolation.
So you still need something between each component and the shelf it sits on. I have Townshend Audio Seismic Platforms (the original, air bladder version), and either the newer Townshend Seismic (spring) Pods (for my turntables), or Symposium Acoustics and Ingress Engineering roller bearings (for electronics). The combination of the roller bearings for lateral isolation and the air bearing for vertical provide pretty effective, relatively cheap isolation from floor-borne vibrations. Active isolation or the Minus K platforms are far better, but at over two grand a shelf, only for those with plentiful hi-fi funds.