Our ventilation holes can effectively control ventilation, effectively prevent outdoor air from entering, and maintain a suitable indoor temperature; it can also block the noise between the ventilation ports, which is very convenient and practical. The exhaust cap is high -quality magnetic material, thick and , strong magnetic, can be perfectly sealed and the exhaust port is perfectly sealed. It not leak and can be used for a long time. The size of the air -conditioning ventilation holes is 30.5x30.5 cm/12x12 inches, which can be cut into the size you want to meet your use needs. Ventilation holes can be widely used in flooring, ceiling, walls, communication ventilation, HVAC, basement, furnace mouth, car, RV, etc. Our products are only suitable for steel ventilators and are not suitable for aluminum or plastic exhaust ports.Not suitable for children under 13 years old. Product Size: 30.5x30.5cm/12x12 inches Colour:As Shown Material:rubber Package Contents: 1 set x square register Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.