TonePros quote -. Saddle Material: TonePros G-Formula Nylon 66. Loads More Tonepros Bridges and stop tails. Locking Graphite 'G Formula' Saddles 'Pre-notched' saddles, Nickel. This new material retains the tone of the original Nylon 66 saddles, but adds other hi-tech ingredients that provide a new “slippery” surface.