1.5 lb tapered 4” to 2.5” EPS foam facilitates water runoff and keeps heat in. These covers are strong yet light weight, making them easy to handle and providing more than-adequate insulation with an R Value of 14.3. Optional 2 lb. Dura Foam upgrades are available. Sunstar uses only virgin foam to provide you with a more durable, more insulated and more water-resistant hot tub and spa cover.