Complete replacement handslide assembly for King model 4B and 4BF large bore tenor trombones (models 2104 and 2104F). 0.547 inch bore. Original OEM item made by King at the Eastlake, Ohio plant. Fits King 4B, 4BF, 2104 and 2104F models current and older,dating at least back to the 1970's. Earlier models might not fit.