075516105 - The seals for the main output shaft [where your front sprocket is] both the inside little and outer large seals available for 750, 860 & 900cc bevel drive twins.
This is the smaller inside one.
You can access this by removing your counter shaft sprocket, then removing the snap ring just inside. You can most likely stuff in 2 or 3 of these seals to help seal this area so I would strongly encourage to order 2 or 3 of these, not just one. Stuff them on top of the existing one, don't bother trying to remove it....