This is a MB uprated fuel resistant float for a Dellorto PH type carburettor. Coloured red to separate them away from genuine Dellorto in White and Black which can fill with petrol and flood. 
 
Fits:
PHBL 22, 24, 25, 26mm
 
PHBH 26, 28 and 30mm carburettors
 
These weighs 7 grams.