For Gibson® guitars, basses, banjos, and mandolins 1-5/8" x 21/64" x 3/16" (41.28mm x 8.33mm x 4.76mm) 12" (304.8mm) top radius Stewart-MacDonald is your source for quality bone! Bone's hardness and density contributes to good tone, it polishes well, and it allows more precise slot filing. Bone is traditionally preferred for making nuts and saddles on quality instruments. Shaped nuts will save you a LOT of work—a head start for the novice builder, and a bonus for the busy repair shop where time is money! The dimensions have been carefully researched, and minor trimming, slotting, and sanding are all that's needed to fit most popular guitars.