The S-5-U and S-5-U Mini clamp are versatile clamps. This clamp is designed to fit vertically-oriented seams and many of the (larger) horizontally-oriented seams. Because of this versatility there is more labor, tooling and machining involved in the manufacture of the clamp. The S-5-U clamp is machined for an M8 bolt on both the top and the side of the clamp. And there are setscrew holes on both sides. So, while the clamp fits more metal roof profiles, it also costs more to produce.