The inside isn t as smooth as straight metal pipe i only use flex duct for air take off s from a trunk duct line to a baffle or air box for a register.
Rigid aluminum dryer duct.
Flex duct comes insulated in a similar fashion but flex duct is more restrictive to airflow.
Semi rigid dryer duct wx08x10075ds ul approved this duct is easy to install with the 2 included clamps at the home depot ge 8 ft.
3 25 4 0 4 0 airflow restriction wastes energy by increasing dryer times and it increases lint build up and the possibility of a dryer fire.
It has a wide rectangular shape except for the two ends where it connects to the dryer and the vent outlet.
Even some readily available semi rigid does not perform as well as dryerflex.
Slim duct sometimes called periscope duct or known by the brands tite fit or skinny duct is a telescoping rigid aluminum duct designed for transition ducting in tight spaces.
If you can use a thicker insulation do cover pipe than the 1 quot.
Even worse flexible ducts are easily crushed which blocks airflow and causes the dryer to overheat which in turn can lead to lint fires.
Dryerflex has a smooth interior similar to semi rigid which allows the dryer to perform at peak efficiency.
Enjoy the 8 ft.