Hello Marius,this is a Dürkopp 291-185081 or 291-185082 machine. The needle system depends on the sewing gauge assembled in the machine. An overview about the sewing systems you can find here:Service instructions are all described in the manual of the machine.I hope this will help you. If you have other techncial questions, please contact our agents:Best regardsDÜRKOPP ADLER AGThomas Brinkhoff
Dear Marius,
the N291 was the successor of the 291. The main reason was a facelift. The machine functions of the N291 are nearly the sameas the of the 291.
The differences of the subclasses:
291-164062:
291-185082: