For a slatted radiator, you need the following number of mounting hooks, depending on your chosen SpeedComfort set: Monoset: 1 set of hooks Duoset: 2 sets of hooks Trioset: 3 sets of hooks Extension set: 1 set of hooks When you select that you need a set of hooks in the shop, the correct number of hook sets will automatically be selected for the chosen product. (not yet available in the UK, soon will be)