FOR 4 INCH DUCT - Insertion diameter is 3.9 inch / 99mm. Wall plate/flange dimensions are 5.91 x 5.91 inch / 150mm x 150mm. Screw hole spacing is 5.31 inch x 5.31 inch / 135mm x 135mm. The duct connector is made of quality plastic with temperature resistance from -5°C up to +60°C. White, simple and stylish. The rigid/straight pipe or flexible ducting adapter is perfect for HVAC ventilation air ducts. Easy to install, compatible with 4 Inch tube. Connect ducting components easily with durable plastic flanges for reliable connections. Easily connected to various types of circular ventilation air ducts. Perfectly suited for ducting your Tumble Dryer, Bathroom or Kitchen extractor fan, Hydroponics, In-Line Extract Fans, or Cooker Hood. We always provide you with premium equipments. Can be installed and used in any climate. The elements can be connected without glues and sealants.