19.85mm Tapered Shaft which equates to 20mm. This was on a generator that failed to produce power / has no throttle but easy to fit one. In Excellent condition / showing some light surface rust here & there. This item is in the category "Business, Office & Industrial\Industrial Tools\Generators". The seller is "star_clearance_sales" and is located in this country: GB. This item can be shipped to United Kingdom.