Never used CKB Acousti-Balance mouthpieces.  These were developed in the late 90's early 2000's as an accessory for Conn (Vintage One), KIng and Benge Flugelhorns.  They are no longer manufactured. They were manufactured for UMI by Warburton Mouthpieces, USA.  This mouthpiece has a LARGE Morse Taper! If you are unfamiliar with tapers of Flugelhorn mouthpieces...here's the explanation:LARGE Morse taperCommonly known as Standard Taper. Fits all Yamaha, Getzen, Jupiter, Callet, Stomvi, Benge, King, Blessing, Conn Vintage One, Weril, Holton, Schilke, older Kanstul 1525 flugelhorns, Austin Custom flugelhorns, Allure, Jupiter, and most other “American” flugelhorns except Bach.SMALL Morse taperThe so-called "Bach Taper." Fits Bach, Courtois, CarolBrass, LeBlanc (including Sandoval), B & S, Taylor, and some other European brands, plus Kanstul models 725, 1025, and newer 1525.FRENCH (straight) taperAlso known as Couesnon Taper, French taper is used by original Couesnons, Flip Oakes "Wild Thing," Kanstul CCF 925, and original F. Besson flugelhorns.