The low grade foam is a 1.1 lb foam. We use a firm foam so you get a great support and don't sink through. This foam is rated for 1-2 seasons of life based on occasional use by an average adult.
 
Sizes:
Cot: 27"x74"
Twin: 39" x 74"
Twin XL: 39" x 80"
3/4: 48" x 74"
Double: 54" x 74"
Queen: 60" x 80"
King: 76" x 80"