The SS method has three steps. In the first step, solve 3/4 of a face. In the second step, finish the face while simultaneously orienting the opposite face. Finally, permute both layers at once. Without counting reflections, there are 60 algorithms, including the 5 PBLs. Including reflections, it comes to 109 algorithms.
"Stern" is the German word for star, making SS the "Star-Sun" method.