Guyker Acoustic Guitar Bone Bridge Saddle Nuts Replacement Parts Accessories for Acoustic Folk Guitar, 2 Piece, Black Lower String Pillow 74x3x9mm ATB-7439For 6 string acoustic guitar. Material: cattle bone, durable and compact. The bone has minimal porosity and a great appearance. Convenient to Use: These genuine bone guitar bridge saddle have pre cut string slots which require very little experience to install and are very simple and easy to use. With minimal porosity and a delicate appearance. Package included: 2 pieces lower string bone nuts.