52-button system. Especially in English-speaking countries, the term Chemnitzer is frequently applied to any of the square German concertinas that are not bandonions. In the United States, especially in the Midwest, where other concertina types are not as well known, it may be called simply a "concertina". There are also Chemnitzer concertinas with 65 buttons (130 notes in total) created by Albert Nechanicky which are called "130 Key Concertinas". The treble keyboard has a 3 octave range from A3 to A6 and the bass keyboard has a complete Bass and Chord System with all 12 chromatic bass notes and 96 chords all of which can be played on both push and pull. They're being revived and are becoming more popular in every genre of music due to their versatility. The 152-key Chemnitzer has 76 buttons and uses an extended layout from the 130, increasing its range and versatility, also being recovered. Chemnitzer Concertinas have up to 4 Ranks of Reeds, although versions w/ 5 (or more) sets of reeds exist & are being recovered. Innovations The most notable innovations to the internal construction of the Chemnitzer concertina were made by German-American instrument builders in Chicago: Ernest Glass patented an aluminum action in 1912 (), which was quicker and quieter than earlier wooden actions; his son Otto further improved this action in 1928 (). Otto Schlicht patented an action in 1932 () which improved the pivot method of the action levers and allowed action levers to be manufactured by bending metal stock rather than by die stamping. In 1910, prior to these improvements, Robert Leppert was issued a patent (), the specification of which describes in detail an action containing jointed levers between keys and pallets, however the claims of the patent only relate to a means of expression control also described; it is not clear whether Leppert actually invented the action arrangement. Albert G. Nechanicky (1909-1986) invented the 130-key Chemnitzer concertina which is fully chromatic, allowing it to play in every key. This innovative concertina eliminates the need to carry several 104-key concertinas pitched in different keys, sometimes built without markings identifying their respective tonalities. He also published a method for his instrument which explains how its layout differs from others. Many American and Italian builders (such as Eagle Concertinas) of the 20th century began using reeds and reed blocks like the ones in accordions as a cost-saving measure, to