Berlin window and gauze fan integrated outward opening window, inclined line pressing,and the frame and fan inside and outside flush design, highlight the sense of space hierarchy; double-layer hollow tempered glass, effectively isolate outdoor noise; three sealing & isothermal vertical, better heat preservation and insulation performance; implicit drainage structure, smooth drainage, standard with windproof and drainage cover, to avoid rainwater back irrigation; standard R3 arc small corner protector, collision prevented, beautiful and durable; upgrade the screen bending process, stable structure, mosquito and insect prevention; optional safety grid device, effectively improve the safety performance.