What's the difference between a ferro rod and fire-starter cubes?

A ferrocerium (ferro) rod throws a shower of hot sparks when scraped with a striker and can light tinder in thousands of separate uses, making it a survival and bushcraft staple. Fire-starter cubes or squares are wax-impregnated wood or sawdust blocks you light with a match or lighter; they burn for several minutes to ignite charcoal, wood, or kindling. Ferro rods suit emergency and camping kits, while cubes are easiest for grills, fireplaces, and fire pits.