Energy-absorbing foam for seats

I used EAR Specialties Confor foam in my plane's seats. I laminated the
three softest 1/2" plies behind my back with a lumbar piece, all four
1/2" ply grades under my legs, and five 1/2" plies under my butt; two
of the hardest, two of the next softer, and one of the next softest.
Even with a wallet in my back pocket there are no pressure points,
which on my five and six hour x-country flights is a real blessing!
Look on McMaster-Carr catalog page 3304, www.mcmaster.com. They get
hard when cold, but will soften and conform as your bod warms them up.
I highly recommend this foam for your seats if you do much
long-endurance flights. I think McMaster's prices are less than you'll
find in ACS. Several of us went together to buy them through the
factory to meet their minimum purchase amount. EAR also has a complete
line of sound-absorbing material for aircraft, and a booklet on their
use.