High density foam has a compression rate of 36 lbs. This means for every 36 lbs. on a general idea, your foam will compress by 25%. High density foam is designed for that sink in effect for those who love to fall into a nice soft cushion. 100% Recovery rate fire retardant durability : durable, medium density foam suitable for long-term use. <br /><br /> Our large foam sheets are ideal for a number of projects, such as: <ul> <li>Seat Replacement</li> <li>Chair or Sofa Cushion Upholstery</li> <li>Fixing or Replacing Bench Pads and Furniture</li> <li>Boat Seats Upholstery</li> <li>Upholstered Headboards</li> <li>Car & Other Automobiles Seat Repair</li> <li>Home and Commercial Applications</li> <li>DIY Projects, Arts & Crafts</li></li> Medical Equipments (wheel chairs and walkers)</li></li> </ul></li> </ul></li> </ul>Warnings: Foam packages need to be opened immediately upon arrival. Do not let foam sit unopened for more than 1 week. Don’t open with a box cutter (you’ll cut the foam). Use a ball point pen or keys. </li> </ul></li> </ul> When unpacking foam, allow the foam to sit for 3 to 5 days so foam can breathe and return to its original size and form.