Good used condition,fits the robin mk1,the kitten all models,and early Rialto,with the carbon bush inside,before the clutch changed,comes with the ring gear,as photos show,will not fit the regal models,thay are different,2.8KG,and the measurements include the teeth 10 1/4” outer diameter,note the 2 lugs for the clutch plate are opposite each other,the Center bush is 1/2” diameter,inside,,thanks for looking.