Hi Trox,
for choseing a binder you must sure which material you sewing and which diameters you need.
you can use the standard but you need a special walking (like 91-049 269-93/006) and presser foot (like 91-040 432-04/005)
but you must know what you will sewing and which materials befor you chose a foot or something else.
the binderinstrument can be 91-045 543-90 but you don't find this in the shop this is to special.
the binderinstrument from pfaff will cost 210 €
if you have any questions you can ask me!
best regards
sewingtec