This type of locking washer is standard on European metric propeller shafts. Any good propeller service shop will know exactly what they are and have them in stock. The only specification needed is the shaft diameter.
Anybody who’s boat uses these should carry at least one spare. It is true they can be reused, but in my experience metal fatigue caused by bending, and rebending, the tabs can cause the washer to fail. Shortly after that happens your propeller falls off—and you have a very bad day.
The safe rule is to use a new one every time the propeller is removed.
Ragged Island, Bahamas