These are ideal to reduce / stop damp in any room. This Product is not suitable to vent gas appliances. MAP HARDWARE ADJUSTABLE VENT (HIT AND MISS) FOR OPENINGS 229MM X 152MM INCLUDES FITTING INSTRUCTIONS CHECK IN OUR LISTINGS FOR OTHER SIZES AVAILABLE PLEASE NOTE THE FOLLOWING POSTCODES ARE SUBJECT TO A SURCHARGE FROM OUR COURIORS, PLEASE ENQUIRE BEFORE ORDERINGTHIS EXCLUDES ROYAL MAIL LISTED ITEMS AB, BT, HS, FK, GY, IM, IV, J, KA, KW, PA, PH, TR, ZE WHY NOT ADD THIS TO YOUR WATCH LIST FOR POSSIBLE FUTURE OFFERS! THANKS FOR LOOKING! PLEASE NOTE THE FOLLOWING POSTCODES ARE SUBJECT TO A SURCHARGE FROM OUR COURIORS, PLEASE ENQUIRE BEFORE ORDERINGTHIS EXCLUDES ROYAL MAIL LISTED ITEMS AB, BT, HS, FK, GY, IM, IV, J, KA, KW, PA, PH, TR, ZE PLEASE NOTE THE FOLLOWING POSTCODES ARE SUBJECT TO A SURCHARGE FROM OUR COURIORS, PLEASE ENQUIRE BEFORE ORDERINGTHIS EXCLUDES ROYAL MAIL LISTED ITEMS AB, BT, HS, FK, GY, IM, IV, J, KA, KW, PA, PH, TR, ZE This adjustable plastic vent is designed for openings up to 229mm x 152mm (9" x 6") and provides an airflow of 4680 square mm when open. This vent is ideal for improving air circulation and addressing issues like stale air, dampness, and odours.