Standard thumb trigger lever for use on Bach model TB200B, 36B, 36C, 36CO, 42B, 42BO, 42BOF, 42C, 42CO, 45B, 50B, 50BO, 50B2, 50B2O, 50B3, 50B3O series tenor and bass trombones. Not for Hagmann or axial flow valve horns (42A or 42AF).
NOTE: This lever is a contemporary build designed to be used with modern miniball linkages. If you have an older horn with the ball and socket linkage, this lever will not work. You will need to upgrade that valve's linkage system instead.