The handle color, and nothing else that matters. Both are 4.5 inches closed with a 3.5 inch satin-finish stainless blade, a nylon handle, thumb studs, a thumb ridge, a pocket clip and an inlay shield. Their Case pattern numbers differ only by an OR suffix on the orange version.
We would rather say that plainly than manufacture a distinction. Closed length, blade length, blade finish, steel, handle material and hardware are identical. Case's own pattern numbers, T0124.5 and T0124.5OR, differ only by an OR suffix.
If you were hoping one had better steel or a longer blade, it does not.
High-visibility handles are genuinely easier to find if you put a knife down in grass, leaf litter or a cluttered workshop. That is a small practical argument for orange, and it is the only functional difference between these two.
Black is less conspicuous, which some people prefer at work.
If you are comparing across the Harley Tec X range, the meaningful differences are size and handle material rather than color. See the CA52161 comparison, which is a genuinely different knife.
Both of these sit in our Licensed & Movie category.
Specifications above come from the manufacturer. Live prices and availability are in the strip below, pulled from the catalog at build time rather than typed into the copy, so they cannot go stale on this page.