This is an Aprilia Head Light Switch for the  Ducati Bevel 750 GT, Sport and SS Green Frame models.  Also for other Italian bikes of the seventies. This is the 2 position switch. With 2 types of mounting: direct to the handle bar or on the perch of the clutch or brake handel.  Very nice part, see pictures. 

Ducati roundcase, Imola, Greenframe, SS, SD, GTS, MHR, SSD, Darmah, squarecase, S2, sport, supersport, Borrani, Ceriani, Scarab, Lockheed, Marzocchi, Brembo, monza , diana, mach, mach1, dm250, dm350, dm160, 160, 450, dm450, desmo, desmodromica, elite, elite 200, brembo, 900SD, Mark 3 , mark 2, CEV, 750, 750GT, 860GT, 900GT, MV Agusta 750 America GT SS