Here is a New Old Stock Commercial Ignition Radio Suppressed Rotor Arm (for Bosch Distributor) for 

Opel

Commodore-C 2.5 E 1981-82

Monza A 2.5E 1981-84

Monza A 2.5E 1984-86 (Sweden, Switzerland)

Monza A 2.8S Coupe 1981-82

Monza A 3.0S, E, Coupe 1981-83

Monza A 3.0S, E 1983-86 (Sweden, Switzerland)

Senator A 2.5E 1984-87 (Sweden, Switzerland)

Senator A 2.5, 2.8, 3.0 S, E 1981-84

Vauxhall

Royale 2.8, 3.0 Coupe 1981-83

Senator 2.5i, 3.0i 1984-87

Viceroy 2.5 1981-83  models.