I have this exact same load, and those banana posts are a much larger size than a standard banana post; that's because they need carry at least 30A which is what the load is rated for. Standard banana posts are rated for only 15A or 20A, and are physically smaller is size than these larger capacity posts. I don't know where you could find the 30A banana posts, I've never seen them in Digikey or Mouser or any other distributor.