NR rear derailleurs came with pulley wheels that are molded in grey MDS nylon, with a co-molded steel insert. 10 teeth. Campagnolo logo is on both sides. Some very late (1985?) NR derailleurs may have slightly different pulleys. The bushing is bronze oil-lite, with a zinc plated steel dust cover on both sides. Mounting hole is suitable for an M5 bolt, and the width is 10.7mm. Later Campagnolo pulley wheels with 10 teeth, C Record etc., in the 10.7mm width, can be used without problem.

I have a few Enduro sealed bearing pulley wheels that I made dust covers to use with NR/SR rear derailleurs. The bearings have ceramic balls, the wheels are Teflon impregnated Delrin. Great shifting and quiet! These are very nice pulleys. $60 a pair plus shipping. $5 in the USA. Jim Merz