Good video!
I have both types of stepped rods, brass and steel.
The steel one also replaces the need for a screwdriver when adjusting/replacing a flint, but is
usually used for knapping when there is
no main charge in the breech, so an accidental spark can't pose a problem.
My other piece of rod is brass, which works great to knap with, but can't be used to adjust/replace the flint.