Quoting Redn 2000
It's a great MOC. But I was wondering, where did you get the triple part for it's arm and what is that inside the helmet?
The triple part in the hand came from the later Bionicle lines, probably the Jetrax T6 and Takanuva. Inside the helmet is another helmet! Unless the inner helmet is what you were talking about, in which case its a minifig helmet.