Louvre grille, 150x150 mm, 175x175 mm, and 210x210 mm – Copper. Mounted with 4 screws. Can be used for all types of ventilation. Insect screen prevents insect intrusion. Dimensions (A×B×C×D×E): 148×148×11×130×130 mm, Air passage: 23 cm². Dimensions (A×B×C×D×E): 175×175×12×155×155 mm, Air passage: 25 cm². Dimensions (A×B×C×D×E): 215×215×13×195×195 mm, Air passage: 123 cm²