 The reeds are arranged around one big reed block with a tone chamber inside, rather than a separate reed block for each row like most accordions.Some Örgelis only have 2 sets of reeds tuned an octave apart, Bandonion-style.The Örgeli with 2 sets of treble reeds of the same octave, tuned slightly apart (tremolo or 'wet'), is called a "Wienerörgeli" (Viennese Örgeli) because of the 'Viennese' tuning (Wienerton) which is widespread among button accordions around the world such as those made by Hohner and the Steirische Harmonika.