3/8" bsp easy to remove / refit top fill plug & rubber ring for the front suspension alloy cross tube as fitted to the DB2 to DB MkIII range,

This plug can just about be undone with your fingers as it doesn't need to be that tight then removed even though the plug is under the radiator, the tube refilled with oil and then the plug refitted.

Doesn't need a spanner,

Also drilled with 1 breather hole that doesn't fill up with dirt.