I had two ws-3 bessey clamps and bought these two to have the right set. However, I misunderstood the size of the ws-6 clamps and realized they were twice the size of the ws-3 when I took them out of the box. But aside from the ws-3 being significantly more powerful than the ws-3, the ws-6 has a much larger cutout where you can place a second piece of wood for an easy butt joint. Also, on ws-6 you can see that both pieces of wood are flush with the ground, while on ws-3 you can only see oneβ¦