The SOPRA XP-20 2 in. x 24 in. x 96 in. Butt Edge Extruded Polystyrene Rigid Insulation is a rigid thermal insulation board made of extruded polystyrene. It is composed of closed cell foam. It is mainly used as a thermal insulation for SOPREMA above-grade wall systems and on the inside of foundation walls. Compliant with CAN/ULC S701.1, Type 3.