Mills bomb

Two body types can be found, horizontal and vertical cast halves. Base screws were made in aluminium, brass and steel. Several spoon types depending on factory. Firing pin has a solid head. Filler plug is normally made of brass.
Typical for all No.5's is the absence of the threaded hole in the base.

Check Dave Sampson's website, he's got them all I think.

Below:
No.5 throwing practice grenades

Left: Factory made out of an original unfinished casting. Unthreaded base.

Middle: Factory made out of an original unfinished casting with the lugs grinded off. The base used to be threaded.

Right: I guess this was a throwing practice first, later converted into a money bank. The base used to be threaded. The filler plug is shut with a tight fitted steel disc.