Concentric. RCL Fabricated Long Reducer For Circular Spiral Ducting 80mm To 800mm  
 

Reducer with a male-end which slides inside spiral ducting tube. Please see the above drop down menu for the duct sizes you require. This brand of circular spiral ducting fitting is designed for air movement in air conditioning and ventilation systems. Light gauge ridged structure for easy installation.

Diameters 180, 224, 280 and 600 are only available for special order.