| Parameter | Value (mm) | Notes / Description |
| Overall Door Leaf Width | 1200 mm | Total width of the combined door leaves. |
| Overall Door Leaf Height | 2050 mm | Total height of the door leaves. |
| Main Leaf Width | 840 mm | Calculated as ~70% of the total width (70% of 1200mm). |
| Sub-Leaf Width | 360 mm | Calculated as ~30% of the total width (30% of 1200mm). |
| Width Ratio (Main:Sub) | 7:3 | Typical ratio for the main leaf to the sub-leaf. |
| Rough Opening Width | 1225 mm | Door leaf width (1200mm) + 25mm allowance. |
| Rough Opening Height | 2070 mm | Door leaf height (2050mm) + 20mm allowance. |
| Door Thickness | 35 - 40 mm | Common thickness for exterior doors (varies by manufacturer). |
A double-leaf door, also known as a "large and small door" or "mother-and-child door," is a double-leaf door consisting of a wider main door (the main door) and a smaller secondary door (the secondary door). In daily use, only the wide main door is opened for easy passage. To transport large items, both the secondary and main doors can be opened simultaneously, creating an extra-wide entrance.This design perfectly balances everyday convenience with the width required for special occasions.
Solid as a rock, protecting your entire home (focusing on safety and performance)
Superior theft resistance: "Made of high-strength materials (such as cast aluminum and stainless steel) with a professional multi-point locking system. The main and secondary doors lock in tandem, and are often equipped with a top and bottom locking bar, securely locking the door leaf to the door frame. This delivers a burglar-proof performance far exceeding that of ordinary single doors."
Excellent sealing: "Multiple sealing strips securely fit the door gap, effectively protecting it from wind, rain, dust, and noise. Whether it's a storm or a bustling bustle outside, the interior remains a peaceful and cozy private space."
Durability: "Thickened door panels and heavy-duty hinges ensure the door remains stable even after years of opening and closing, preventing any sagging or deformation."
Thoughtful and practical, details speak for themselves (focusing on functionality and convenience)
Ingenious ventilation and lighting: "When ventilation is needed, just open the sub-door and hang the screen door. This maintains air circulation while effectively preventing mosquitoes from entering, while also ensuring privacy and security."
Humanized design: "For families with elderly, children, or wheelchair users, only the main door remains open for daily use, providing ample width for unobstructed passage. When needed, it also provides a wide, barrier-free passage, demonstrating all-ages care."





