A peal of eleven electrically operated bells, cast in 1960, hangs in the soaring south tower. Replacements for other ancient bells also lost in the 1945 fire, they are used during Masses at the cathedral: four are used for an ordinary Mass; the quantity increases to as many as ten for a major holiday Mass; and the eleventh and largest is added when the Cardinal Archbishop of Vienna himself is present. From the largest to the smallest, they are named the "St. Stephen" (); "St. Leopold" (); "St. Christopher" (); "St. Leonhard" (); "St. Josef" (); "St. Peter Canisius" (); "St. Pius X" (280 kg); "All Saints" (); "St. Clement Maria Hofbauer" (); "St. Michael" (); and "St. Tarsicius" (). Also in this tallest tower are the "Primglocke" (recast in 1772), which rings on the quarter hour, and the "Uhrschälle" (cast in 1449), which rings on the hour.