Guten Tag heu,
While NN3 will have the bare components to work for you including the 15/18 degree click stop detent ring and rail stops with little baggie of extra parts. It is strongly advised however to buy the NN3-II package. Only $30 more it is excellent value and you get a set of 3 added rings (18/20, 25.7/36, 45/60 - good if shooting at different focal length), a camera plate for more secure camera body to NN mounting (good for heavier setups), and a very nice hard shelled case.
Bill