The OF bodies were made of two thin sheet steel halves, with a threaded neck to fit the fuze.
Their designations were the same as the F1's, and so they carried the name of the fuze type.
Several colour schemes are known as you can see in the pictures.
Can anyone shine a light on these different colours? What do they mean in what period of time? Please let me know.

1915 model:
Length :123mm
Diameter : 60mm
Filled weight : 250gram
Filling : 150gram Cheddite or 120gram Schneiderite