They are the same, but halo the h5 one has "teeth" In the back. If you look it up and see the picture of an dude holding a irl black metal one, that's what it looks like... what are you making it out of? I tried foam but that's not a great idea for blades. Polystyrene? Or probable fibreglassresin now I think of it
You can defienetly get away with a heavier material though, since it is a smaller prop. I like the idea of using rubber stunt knives but its hard to find one that is exactly the design you want. Maybe modify something existing?