Note: this cap can be difficult to connect to the reservoir, it is designed for a tight seal, attaching the cap is a three step process
1) Align tabs with cutouts on reservoir
2) Push cap down until it seats
3) Twist to seal.
The cap will not connect to your reservoir if you push and twist at the same. time.
Works on most European cars, including Alfa Romeo, Audi, BMW, Fiat, Mercedes, Peugeot, Porsche, Renault,...
Works on most imported and late model cars that do not have a screw on...
Works on most Air Cooled VWs, including Bugs, Buses, and Square Backs and Fast Backs....