Profile: Kestrel Aluminium Systems Ltd. supplies a wide range of high quality aluminium extrusions and accessories for the fabrication of shopfronts, commercial doors, curtain walling, windows and glazed roofs. Our 50mm casement window system is designed for intermediate commercial applications and is internally glazed. It can accommodate single glass 6mm or 6.4mm thick and double glass sealed units 24mm or 28mm thick. Handles for use with espagnolette slide bar locking can be used with this system as can cockspur locking handles. A range of friction hinges are available including non-restrictor, restricted and sterling heavy duty.