Screw:
Looking at my records, I installed Bosio nozzles in my 1983 300CD on 14 August 2014 and so far have 50532 miles on them. They are well worth the money and trouble to find. The immediate difference in the way my engine ran compared to the OE Bosch was remarkable. I bought them on-line by Googling "Bosio" and had them shimmed to spec and spray tested at a local Diesel truck engine shop.

Prior to purchase, I asked the Greazzer how long they should last. His answer was "At least 100k miles." I suppose the Monarchs may also be better than the Bosch (I understand they are now made in India) but when it is time to replace, I will search again for Bosio.