Earthwool Dritherm Cavity Slabs are semi rigid or rigid slabs manufactured from non-combustible, water repellent glass mineral wool. Manufactured at 455mm wide to suit standard vertical wall tie spacings ensuring a closed joint with adjacent slabs. The 50mm and 65mm Dritherm 37 Standard are manufactured respectively to 0.035 W/mK and 0.036 W/mK lambda respectively. The higher specification allows the thinner 50mm and 65mm materials to achieve a robustness normally associated with thicker materials and allows for easier installation. Earthwool Dritherm is desaigned to fully fill the cavity. Earthwool Dritherm Cavity Slabs represent no known threat to the environment and have zero Ozone Depletion Potential and zero Global Warming Potential.