Of all the components that make up this Oil Filter / Oil Pump the Screw Cross 6x18 has the lowest price.
Parts such as the Oil Filter / Oil Pump: Nut Lock 16mm, Pin,lock,8mm, Spring,oilthrough, Through,oil are included in the Tl250 Trials 1976 Usa Oil Filter / Oil Pump parts fiche.
On this parts fiche the O-ring 7x1.7 is the most specified component.