Washer Fits Ford Massey Tractor Fits:Ford- 9N, 2N, 8N, NAA, Jubilee when using 2-1/2"" diameter piston- Massey- TE20, TEA20, TO20, TO30, F40 TO35, 50 when optional 2-1/2"" diameter piston - Specifications For 2-1/2"" diameter lift piston Replacement Numbers: Ford- NAA473A- Massey- 0- This back up washer installs behind the o-ring, (o-ring installs toward the head of the piston) All JJAgParts items have been hand selected by our team and are continuously monitored for Quality. Should a craftsmanship or fitment concern be identified, JJAgParts will work with you to stand behind our products. JJAgParts is an American owned and operated family business! Here at JJAgParts, we strive for customer satisfaction. If you are not satisfied with your order, please contact us so we can make it right. Note: OEM Part Numbers are for reference only and should be verified before purchase.