DELTA® Mitered Fittings is a nominal 8 pound density Preformed half- cylinder pipe insulation manufactured from mineral wool bonded together with a high temperature binder. It is produced to fit precise NPS and tubing pipe sizes for commercial and industrial applications ranging from -20°F(-29°C) to 1200°F*(649°C*). DELTA® Mitered Fittings mineral wool incorporates an additive which makes the insulation water repellent*.