Fakro DXC-C P4 Secure Flat Roof Window Fixed Dome & Kerb - 900mm x 900mm. Please note this is an extra secure anti-burglary double glazed unit with a single polycarbonate dome. This is a fixed, non-opening dome & kerb. The DXC-C P4 Secure flat roof dome is an innovative double glazed unit with laminated internal glass which is extra secure anti-burglary P4 class as standard. The dome is made of durable polycarbonate. Should the pane crack, shards of glass do not pose a danger due to the internal laminated film. Highly resistent to adverse weather conditions such as hail. A specially profiled covering material under the drip cap of the frame facilitates the finishing of the window connecting with the roofing material. The flat roof window can be also mounted on an additional base with a height of 15cm, which raises the window and allows it's installation eg. in green or living roofs. Dimensions Dome size: 900mm x 900mm. Minimum roof opening: 900mm x 900mm. Maximum roof opening: 950mm x 950mm. uValue: 1.2W/mk. Upstand: 150mm.