The Loaf Pinches are shaped to have a "bread loaf-like" profile. The sides of the holds run parallel to each other, forcing the climber to pinch. The contour around the sides has a bulge creating incuts to make the pinching action comfortable and more accessible when set on steeper walls.
Set #1 has subtle 1/4" to 1/2" deep incuts, which is just enough for the beginner to latch on to when using them on vertical walls.
You can expect Set #1 to feel in the V1 range on vertical walls, V2 on 25-degree walls, and V4+ on 45-degree walls.
Set #1 is the most positive, and Set #3 is the least positive.
You may also be interested in these other sets of Loaf Pinches.