Many mistakenly take high density foams as firmer foams but that is not the case. A foam that is 44 ILD in a medium and high density will feel the same.
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.
****Disclaimers****
Many advertise their 1.8 density foam as high density which is false advertisement. When looking at foam products you should look at the ILD / Compression Rating ( Firmness and Softness ) of the foam and Density ( Lifespan / Durability ) of the foam.
Sunlight will turn this unit from white to yellow, if you do not want a color change on your unit we suggest keeping it away from direct sunlight.