Question about horseshoes- what is the difference between....?

theyre called clips for future reference, they help to keep the shoe from sliding back. some horses cant use the kind with one clip in the front because of the way their hoof is shaped, like some horses need a more "squared" (not a square hoof, but the toe isnt perfectly round) hoof, while others have the nice round toe. if you horse has a round toe he should be fine with just the 1 clip. I typically see the double clips more on the back feet, than the front.