If you own a Post-1948 norton model - i.e. with the oil drain sump plug in bottom of the crankcase - then it will either have been fitted with 1/8" BSP sump plug (see also our Sump Plug listing - Item 1101 for more information on different sump plugs) - or sometimes a 7/16" threaad plug - If your sump plug has a thread that measures 7/16" OD - then these are the correct fibre washers for that plug.
This red fibre washer was also used used at the back of the SOHC Cylinder Feed Bolt (i.e. the drive side), normally behind a steel washer (but bolts can be different lengths or crankcases have different bores, sometimes the bolt is not long enough to fit both), to prevent seepage of oil .
Price is for 2 washers