Musiclily Round String Retainer Rondelle String Tree Guides Set for Jazz Bass/Precision Bass Guitar Replacement, Chrome(Pack of 4) Used on the majority of Precision and Jazz Bass This string tree provides better nut/bridge contact for bass strings High shaft height: 7mm, low shaft height: 3.5mm;Size: approx. 19mm diameter Mounting screws are included. Package Included: 4 Pcs String Tree With Screw.