In June 1811 Crusell made another trip to see Tausch in Berlin, and the two men discussed clarinets. Later that month he visited a benefactor in Leipzig, and in July he purchased a new instrument from Heinrich Grenser in Dresden. His Grenser clarinet was an advanced design for the time, with eleven keys. (A picture of Crusell's Grenser clarinet can be found here.) Later, in 1822, he again went to Dresden and purchased additional clarinets from the Grenser shop's successor, Grenser & Wiesner, and from another maker by the name of Bormann. The Stockholm Music Museum possesses five clarinets made by Grenser & Wiesner in 1822 or later, four with eleven, and one with ten keys.