Durable and resilient, constructed of our premium foam with a density that prevents collapsing. These cushions will keep their shape and keep your finished project beautiful through high use and time. May be easily trimmed with an electric carving knife. We can also cut to size/shape for you at no additional cost. Firmness Options: Density 2.5 - Compression 38 (ILD) - Very soft. The Medium Firm Qual 0500 is best used as a topper in 1"-1.5" thickness, or as a very soft cushion in 2"+ thickness. Density 2.5 - Compression 50 (ILD) - Most commonly used. The Firm Qual 0800 provides a balance between comfort and firmness. Density 2.5 - Compression 65 (ILD) - Very firm. The Super Firm Qual 0900 is a satisfactory choice when you require a 1-2" piece of foam without the worry of sinking through it. Very commonly used for bar stools.