[High-Quality Materials & Durable]: This photo frame mat is made of high-quality paper material, featuring environmentally friendly properties, resistance to deformation, anti-aging, and durable construction. Designed to be acid-free, it ensures safe use without producing any toxic or harmful substances. [Standard A3 Size & DIY Design]: The outer size of this photo frame mat is 29.7 x 42 cm (11.69 x 16.54 inches), suitable for A4 size pictures. The white color allows for easy customization, enabling you to create a unique frame based on your personal preferences or picture style. [Centered & 45-Degree Bevel Cut Design]: This photo frame mat features a dual-frame design with a smaller frame positioned in the center of the larger frame, optimizing picture presentation. The inner frame edge includes a 45-degree bevel cut for a refined finish. [Easy to Install]: This photo frame mat is simple to use and requires no tools or special skills. Just remove the back panel from the frame and insert the mat directly. [Excellent Photo Frame Mat]: This mat effectively conceals uneven edges caused by cutting or sealing processes. It securely holds smaller pictures or artwork in place, preventing slippage. A practical and reliable choice for picture framing. Color: White Material: Paper Package Contents: 10 x Picture Frame Mounts Note: Light reflection and differences in display screens may cause slight variations in color compared to the actual item. Measurement error is +/- 1-3 cm.