This is a set of full length PVC strips which hold the glass along the full length.This gives a far neater finish plus it is a lot easier to keep clean because the clips are no longer used. Your whole greenhouse is stronger in the wind when bar capping is used. The capping is a similar shape to the stainless steel clip and it clips in,in a similar way- the difference being that the PVC is the full length e.g. 5' long).You can only use bar capping with the whole sheet toughened glass (because it won't go over overlaps).