These packers are designed for use during the installation of the window frame into the window reveal, exactly as with a spring frame packer. However, the design incorporates a “klip” function and installation “tab”.
This klip exerts a lateral force between the frame packer and the fixing, holding it in place preventing any rotation of the frame packer and it falling out.
The additional tab makes the location of the frame packer even easier, especially when working at height and once the window is in position the tab is bent over, breaking off.
The advantages of this design are that once in position it can be released by the installer, freeing up a hand to install the fixing correctly, easily and safely (especially when working at height).