150mm Ducting is used for high power cooker hoods, generally any cooker hood with a motor extraction rate of between 750 m³/hr to 1750 m³/hr, These ducting components are generally used on all ceiling kitchen extractors and outside motors, the rule of thumb is, the bigger the ducting used the better! we always recommend that you check out our technical information on each product page as this will determine what size ducting you will require for each model based on the size of the motor.