This is for a throttle needle to fit original Amal Type 29 and 89 (Pre-War) and Type 289 carburettors - i.e. the type with seperate floatchamber, a slighlty bigger version of the 276. These were fitted to a number of marques in the 30's - 50's, most notably Vincent singles and twins, up until the end of 1954, i.e pre-Monobloc.
Price is Each
I am not sure if the Type 29/89 or 289 were fitted to any Norton models (it was more normal for Norton road models to be fitted wtih either the 76 or 276 Amal carb), but they may have been - just check the number stamped on the flange of the carb.
They were commonly fitted to Vincent models as well as many other British marques
These needles are UK manufactured by a specialist manufacturer to the oiriginal Amal needle dimensions