Density is the lifespan of the foam, the higher the density the more material is used to make the foam hence making it last longer. ILD / Compression Rating Explanation #941 in Cushion & Upholstery Foam, Item Weight 10., 42 pounds Manufacturer Top Shelf Value Date First Available June 23, 2019 Foam Pads 3 Inch Foam GoTo Foam 5" Height X 25" Width X 50" Length 44ILD Firm 541751 High Density Foam Cushion Foam Rubber Padding 4 Inch Thick Cushion & Upholstery Foam Goto Foam 6 Quot Height X 24 Quot 635678 Will last 7 to 10 years ( Depending on use ) , Density : 1., 8 , 43lb compression If you would like to customize this unit please send us a message before any purchase. This units does not have any fire retardants chemicals added to it. Product Material is polyurethane. Compression means the number of pounds necessary to compress the piece of foam by 1 inch in a 7x7 inch area. This product is made in USA. ****Disclaimers**** Many advertise their 1., 8 density foam as high density which is false advertisement. GoTo 44ILD Firm Foam Pad 3x24x72 - Ideal for Upholstery Cushions... This foam features the perfect amount of cushioning and stiffness 5., 0 out of 5 stars Best Sellers Rank #369,466 in Arts, Crafts & Sewing (See Top 100 in Arts, Crafts & Sewing)