Columbia series is a broken bridge window and gauze fan integrated outward opening system window. The window and gauze fan integrated simple style design and the frame and the inner fan flush, full of aesthetic feeling, three-dimensional sense is stronger. At the same time, the gauze net is connected with the profile, which greatly enhances the impact resistance; which is ensuring the anti-mosquito effect and not affecting the indoor lighting. Heat insulation strip is designed on the same vertical line to achieve excellent waterproof sealing, soundproof and heat insulation performance.