[Duct Reducer]: For connecting two ducting of different diameters or for connecting hose to inline fan/exhaust vent. Either flexible duct or rigid sheet metal ducts can be used and save you space [Size]: On one side there is a 6 inch Female Spigot - Will fit into 6 inch ducting. Outer Diameter-151mm, Inner Diameter-146mm. On the other side there is a 4 inch Male Spigot - Will fit into 4 inch duct. Outer Diameter-99mm, Inner Diameter-94mm,Overall thickness 2.5mm, height-110mm [Application]: duct reducer designed for widely used, such as air-cooled hoods, garage, attic, bathroom kitchen extractor fan, hydroponics and HVAC ventilation systems, plastic rigid ducting is perfect for DIY and trade use [Easy to Install PVC Reducer]: No tools are required to install the duct adapter and our calibre makes it easier to fit your duct on Ideal for all tumble dryer vent pipes / hoses, bathroom vents & extractors, air conditioning units, kitchen fans & vents, heat transfer and ventilation systems, gas & electric dryers, cooker hood extractors, as well as a wide variety of industrial,DIY and trade uses. Note: Before purchasing, you need to measure the inner and outer diameters of the connecting props, the inner diameter of the hose needs to be larger than the outer diameter of the reducer, and the fan needs to be smaller than the inner diameter of the reducer Colour:White Material:plastic Specification:100-150mm Package Contents: 5 x Duct Adapter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.