As its name suggests, this fin is more slender than traditional full pivot fins.  Its more upright rake and consistent width all the way to the tip provide more overall area and hold than a flex style fin and is looser and faster than a full pivot design due to its surface area and moderate foil.  It is a wonderful fin that is balanced between stability and looseness and works well in square tail boards as well as rounded pin tails.  Consider it an all-around fin with a bias towards noseriding – best of all worlds