IKOTherm III 25 PSI Grade Polyisocyanurate Foam Insulation is constructed of a non-organic coating bonded to a fiberglass strand mat, offering superior dimensional stability and resistance to moisture. As a rigid polyisocyanurate foam insulation, IKOTherm III 25 PSI Grade has a high thermal R-value that provides outstanding insulation protection, which helps to reduce heating and cooling costs.