The strip material moulds could be used for casting:
-low leads (the same height as a low space/quad),
-high leads (the same height as a type body without character), usually for supporting long ascenders/descenders or for casting ornamental lines (with a matrix above)
-and finally FFR - whose height is the same as the "normal" type has, and the whole surface will be printed. So, a 12 or 18pt FFR would give you a very thick straight line.
There were also TUS ("tie-up slug") mould accessories, but I don't see why that would need any special equipment. You can use normal leads for tying up your type.
Some moulds had equipment for FFR and others did not, it was marked on the box.
The equipment included mould blades, replaceable sideblocks (at least for 1...3 points - I don't remember if 4...18 had them as well) and a flat upper blank matrix.