A Series stilts features a tri-point design and one metal pin for support on each arm (great for lightweight work), the B Series features a row of multiple metal pins on each arm. This feature makes the B series great for propping up flat fully-glazed items that may have a tendency to slump if supported in just a few spots -- think tiles and flat plates. The multiple contact points also make the B series a good choice for supporting smaller, but heavier works.