New BSA Pre-Unit Twins & Singles Speedometer Nacelle Mounting Rubber Grommet. This Rubber Grommet installs in your Headlight Nacelle around your Speedo to keep Water & Debris out! O.D. Measures approx 3 3/4″ & the I.D. measures approx 3 1/4″. Fits many BSA Pre-Unit Twins & Singles with the Speedo in the Nacelle (A7, Shooting Star, Goldenflash, A10, B31, B33, Etc). Please refer to your parts catalog for proper fitment.*****Please note that this Rubber Grommet will not work with BSA Unit Twins as they are different!*****Made in EnglandO.E.M Part number is 67-5088