Simply Push into position, twist to fix, unscrew to remove. The FFS pot hanging cowl comes with integrated rain cap and bird guard allowing the chimney liner to be installed without removing the pot, also prohibits entry by birds and provides increased rain protection. It is used at the top of the chimney pot to take the weight of the liner, this terminal is secured to the flex using the Fast-Fix Screw adaptor built into the cowl, so no need for jubilee fixing bands. Only fits MI-flex.