Vintage Coarse Knurl: -1.188 in. intended for deeper bodied guitars such as the Gibson® Les Paul® Standard or Gibson® 335 model -0.750 in. intended for thinner body style instruments such as those built by PRS® and models like the Gibson® SG, or Les Paul® Junior Fine Modern Knurl: -1.250 in. made to fit guitars with a deeper body depth for more strength in mounting and utilizes standard US internal thread. -0.875 in. standard stop bar tailpiece anchor bushing fits most guitars