Kair Airbrick Grille with Surround for 204mm x 60mm Ducting External grille dimensions: 230mm x 85mm. Needs part DUCVKC5608G to fit inside 204mm x 60mm rectangular ducting pipe such as Kair DUCVKC5604 flat channel. Alternatively use with DUCVKC247 Airbrick Adaptor to connect with 110 x 54mm rectangular ducting. Static Pressure Drop in Pascals: 15 l/s = 6.000 Pa - 30 l/s = 18.40 Pa - 60 l/s = 71.90 Pa. Free Area: 7,680 mm2 Suitable to use in compliance with Part F Building Regulations. Kair 100% Satisfaction Guarantee. Perfect for flush fitting against ceilings and walls. Perfectly suited for ducting your Bathroom or Kitchen extractor fan, Hydroponics, In-Line Extract Fans, Tumble Dryer, or Cooker Hood. This item can be used as a part of a long duct run. Compatible with the extensive Kair ducting range of fittings, outlets, and grilles. For the full range of compatible products please search for Kair Ducting in the search bar. Also fits other ranges. If you have any questions please do not hesitate to ask fellow purchasers via the Customer Questions & Answers system below.