Kair Gravity Grille 100mm / 4 inch with Round Spigot Plastic 100mm / 4 inch air exhaust outlet round vent with non-return shutter flaps which close automatically when not in use to prevent unpleasant odours noises or draughts flowing back through your duct into your property. 4 inch / 100mm round male spigot on the back of the grille fits inside most comparable size pipes/hoses such as Kair 100mm Round Female Duct Pipe Part: DUCVKC250 or 102mm flexible hose Part: DUCP002/102/35. Easy to install just push-fit together & seal if required using a method of your choice (Popular options include Mastic Sealant Poly Cement or Tape). Perfectly suited as an outlet for your Bathroom Toilet or Kitchen extractor fan Hydroponics In-Line Extract Fans or Cooker Hood. Genuine Kair Product & covered by the Kair 100% Satisfaction Guarantee. Unlike generic imported products Kair products are made in the UK and are compatible with the extensive range of fittings outlets and grilles in multiple sizes to offer your a complete solution for all of your ventilation needs. This item can be used as a part of a long ductwork run for a variety of purposes including whole house ventilation, passive stack vent, positive input ventilation, air conditioning, HVAC, and Heat Recovery systems. Kair SYS-100 plastic rigid ducting is perfect for DIY and Trade use and provides superior airflow performance and durability versus flexible duct.