Roman blinds with 1:4 ratio mechanisms are suitable for any size blind, big or small with heavy fabric. This type of mechanism is a geared drive so it folds the roman up slower than what a 1:1 mechanism would, but it is easier and smoother to operate.
In all cases, this mechanism requires a continuous chain, which should be installed no less than 1500mm from the floor and tensioned in a P Clip tensioning device on the wall.
This mechanism fits a 5mm square tilt rod, and will come complete with an idle end cap too, per the image.
We recommend a maximum fabric weight of upto 6kg when using this control.