A balance with an off-center beam can be almost as accurate as a scale with a center beam, but the off-center beam requires special reference masses and cannot be intrinsically checked for accuracy by simply swapping the contents of the pans as a center-beam balance can.
Penolope "Penny" Halliwell (also known to her family as Grams), played by Jennifer Rhodes, made her first appearance during the season one episode "Is There a Woogy in the House" 53 A powerful woman, Penny possesses the power of telekinesis 50 and the skill with it to deflect or reflect many spells or powers used by evil adversaries.