These are the fibre washers that fit the drain plugs fitted on single cylinder (i.e. OHV and Sidevalve) models from 1948 - 59. These models are identifiable in that the drain plug was fitted underneath the sump area, as per these photographs.
Prior to 1948 the drain plug for OHV/SV models was normally at the side and had a different drain plug - we also stock the fibre washers to fit that type - Item 0941. If you have a SOHC model, that will normally also be the side fitting type and require Item 0941 instead.
Price is for 2 washers. Although only one is needed per fitting, it is normal practice to replace them regularly after an oil change.