These products use VT special microporous, microcellular open celled polyurethane foam. It was 
developed in order to exhibit the following attributes:        

• Excellent vibration damping /isolation performance 
• Exceptional  resistance to  compression-set resistance (collapse)
• Extreme  impact absorption ability enabling durable, long-term cushioning performance. 
  In side-by-side drop weight tests, it outperforms vinyl sponge, neoprene  sponge, sponge rubber,
  latex foam and solid viscoelastic
• Ability to withstand constant, repeated deflection
• Supports stability and balance
• Highly flexible
• High density and resiliency
• Will not become brittle and crumble
• Non corrosive to metal
• Extreme stable performance over a broad range of temperatures

Still think that these high tech products are just “any old piece of foam”