A polishing system configured to polish a lap includes a lap configured to contact a workpiece for polishing the workpiece; and a septum configured to contact the lap. The profile elements are designed as uniform standard parts, and in that at least some frame members of the frame structure are provided with means to vary the moment of inertia, where the means can comprise at least one element which is received in said core element and which extend over essentially the entire length of the frame member. The orientation indicator can include visible markings on portions of the side balloon or on inflation segments coupled in fluid communication to the side balloon. The source driver also includes an output switch impedance control circuit 16 that controls the switching operation of the output switching circuits 17.