Stable structure; sound texture Aluminum circular window has below details: -Thermal insulated aluminum with white color. -5/9/5mm or 4/16/4mm double termpered glass, clear. -European accessories. -Top is tilt opening, bottom is fixed. -Minimum diameter: 500mmPNOC is a professional company engaged in production of aluminium /UPVC windows, Aluminum Folding Door, railings, iron/PVC fences, carports ...