High quality waterproof foam board made for RC plane and jet building. Both sides are laminated with strong PVC, not ordinary paper. This is Depron-style Extruded Polystyrene XPS closed cell foam - stronger and more rigid than regular EPS Thermocol.Lightweight at just 200g per sheet but very strong. Easy to cut, sand, and bend. Perfect for scratch building RC planes, jets, boats, and prototype models.