The Crystal GRP Front door Back Door Open in Clear Glass is double glazed using a high energy efficient toughened safety unit. The GRP skin and high density polyurethane foam core offer stability from the elements and water ingress, along with exceptional thermal efficiency helping to reduce energy bills. High security Locking system that Works With Kubu - an Intelligent Alerting System for windows and Doors, installed and ready to go. Comes with handle, low aluminium threshold and PVC cill. It measures with the overall height including the cill. All products are handed viewed from the outside. Kubu door sensors work hand-in-hand with the most secure multi-point door locks available and the cylinder of your choice, to provide just the right level of technology that enhances your home security.  Designed to be completely concealed, Kubu provides discreet, yet helpful Smart security benefits – without having to compromise the aesthetics of your home with unsightly surface mounted sensors or oversized ‘Smart’ locks.