Manthorpe Thermal Cavity Closer Double Flange 50X2440MM G24050 Heat loss & condensation through un-insulated door & window reveals can ruin an otherwise warm & comfortable home. The Manthorpe range of Cavity Closers offers an economical solution to closing the cavity at window & door reveals while also solving cold bridging problems. Cavity Closers not only provide a thermal break at the reveal of both door & window openings, they also act as an effective vertical damp proof course (DPC), ensuring compliance with building regulations. The Manthorpe Cavity Closer also addresses the issue of condensation & promotes an air tight detail. Thermal efficiency can be achieved assuming that all other relevant work has been done in accordance with best practice. They also save time in construction by closing the cavity without the need to return the block work.