Star chart narrow side five-gauge sash window, the wall thickness of the profile is 1.8mm, in line with the new national standard; the lock hidden design with extremely narrow frame, the opening area can reach 50%, better ventilation and lighting effect; double row pulley design, good load-bearing capacity, smooth pushing and pulling: double layer hollow tempered glass with warm edge strip, thermal insulation performance is excellent; multi-channel sealing wool sliver overlapping, effectively reduce track air convection, improve the overall sealing performance; rail sinking hidden inclined surface drainage structure, rainstorm drainage is still smooth without rainwater backflow; indoor handrail / invisible high permeable yarn mesh / guardrail clothes rack can be installed.