Products > Kooltherm > Kooltherm Cavity Closer / Cavity Closer PLUS > Overview Kooltherm Cavity Closer / Cavity Closer PLUS Insulated cavity closer for closing cavities around openings in masonry walls Kingspan Kooltherm Cavity Closer Properties Download PDF Thermal conductivity 0.022 W/m.K Sheathing PVC-U extrusion J-section Core Premium performance rigid thermoset modified resin insulant manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP) and a low Global Warming Potential (GWP) Length 2.4 m Widths Available 100mm, 125mm, 150mm.