This drawing shows an example of a fixed perimeter blast resistant window manufactured by Frontline GB, a specialist blastproof doors and windows manufacturer. It has a double-glazed unit with a laminated pane used on the inner leaf. The plastic interlayer holds the glass in place in the event of a blast and prevents injury to people inside the building. The frame is stronger than conventional windows because the force of the blast wave is transferred to the frame by the glass rather than being dissipated through the broken window inside the building. Because the glass will deflect inwards from the blast, a deep rebate is needed to hold the edges of the glass in place, otherwise the whole pane could pop out of the frame and cause serious injury. Substantial anchor bolts are needed to fix the window to the building structure with the frame attached to the anchors by a series of heavy metal struts.