Because they can I guess.
Sizing and naming of sizes appear to be proprietary (silly I know). About as silly as electronics companies having their own memory sticks which only fit their products (that's right Sony and Olympus, I'm calling you out :lol: ).
Sizing and naming of sizes appear to be proprietary (silly I know). About as silly as electronics companies having their own memory sticks which only fit their products (that's right Sony and Olympus, I'm calling you out :lol: ).