The Serta Blue Fusion 300 Mattress was designed and built with your comfort in mind. It combines TempActiv ™ Gel Memory Foam with a layer of EverCool ® Fuze Memory Foam for enhanced cooling comfort that also supports every curve of your body. It comes with gel memory foam on the top layer, which will help with cooling. Serta iComfort Blue 300 Firm Mattress Review. Click here for current reviews of Serta iComfort models. Updated January 16, 2020. Our mattress experts tested every Serta iComfort model in our research facility and you can … It combines two layers of EverCool Fuze foam and a plush pillow top along with the company’s proprietary TempActiv Gel Memory Foam and a support system made of hybrid coils. It isn't for everyone because of its firmness, but those who do need it are generally happy with their purchase. The Serta iComfort Blue 300 is a firm memory foam mattress that is best for stomach sleepers or those of heavier builds. The Blue 300 Firm is a firm feeling iComfort mattress as its name suggests. This model has been discontinued, but we are leaving the review available for your convenience. Some had issues with durability. The Blue Touch 300 Firm model combines the feel of an extra-firm mattress with the benefits of Serta’s TempActiv ™ temperature regulation system.