Husted of Chicago produced a slide soprano saxophone. During the 1920s some straight alto and tenor saxophones were produced by Buescher, which proved cumbersome to handle and difficult to transport. Buescher custom produced one straight baritone saxophone as novelty instrument for a vaudeville performer. C.G. Conn introduced two new variants in 1928–1929, the Conn-O-Sax and the mezzo-soprano saxophone keyed in F. The Conn-O-Sax is a straight-conical bore instrument in F (one step above the E alto) with a slightly curved neck and spherical bell. This instrument, which combines a saxophone bore and keys with a bell shaped similar to that of a heckelphone, was intended to imitate the timbre of the English horn and was produced only in 1929 and 1930. The instrument has a key range from low A to high G. Fewer than 100 Conn-O-Saxes are in existence and they are highly sought by collectors. The Conn mezzo-soprano experienced a similarly short production run as the economics of the Great Depression curtailed the market for what were regarded as novelty instruments. Most were expended by Conn as objects of repair training exercises. The most successful of the unusual 1920s designs was the King Saxello, essentially a straight B soprano, but with a slightly curved neck and tipped bell, made by the H. N. White Company. Such instruments now command prices up to US$4,000. Its lasting influence is shown in the number of companies, including Keilwerth, Rampone & Cazzani (altello model), L.A. Sax and Sax Dakota USA, marketing straight-bore, tipped-bell soprano saxophones as saxellos (or "saxello sopranos"). Interest in two 1920s variants was revived by jazz musician Rahsaan Roland Kirk, who called his straight Buescher alto a "stritch" and his Saxello a "manzello.". The Buescher straight alto was a production instrument while the manzello was in fact a Saxello with a custom-made large bell and modified keywork. More recently, the mezzo-soprano, or a modern variant of it, came into use by jazz musicians Anthony Braxton, James Carter, Vinny Golia, and Joe Lovano. Some of the 1920s experimental designs, in addition to the Saxello, provide the basis for similar instruments produced during the modern era. Straight altos and tenors have been revived by Keilwerth, L.A. Sax and Sax Dakota USA. A mezzo-soprano in the key of G has been produced by Danish woodwind technician Peter Jessen, most notably played by Joe Lovano. This instrument is more in the timbral quality