Gotoh® 4 In Line Res-O-Lite Replacement Tuning Machines For Pre-CBS® Fender® Basses Bass guitars have weighty machine heads and by their very nature have always suffered from "neck-dive". With the advent of 5 and 6 string basses, this tendency became still more acute, making long sessions uncomfortable for the musician. The RES-O-LITE series was developed to solve this problem. By chiefly using the special alloy "duralumin", excellent weight savings are achieved. By use of the Rock-Solid mechanism the GB350 transmits string movement more powerfully, whilst retaining tuning and giving a smooth winding experience made to pre-CBS Fender® specs and mounting pattern.[SKU:GBR640N L4] Gear Ratio = 28:1 Post Height: 1.21 in. Post Diameter: .55 in. Bushing Outer Diameter: .637 in. Bushing Inner Diameter: .565 in.