Material: Mussel Shell. Instrument: We recommend Shell Tones for Electric Guitar & Arch-top Jazz Guitar. Tone: Mother of Pearl is a hard material that gives bright and sometimes quite brash tones. The hardness makes it most suitable for light picking where clear bright tones are required. Design: Shell Tones are designed around our classic 351 shape. They are machine ground to a precise perimeter at 2.5mm thick. A two-sided chamfer is then ground by hand giving a playing tip of 0.7mm thick. Contents: This pack contains 1 Mussel Shell Guitar Pick. Notes: Although we have tried to ensure that our photos represent the Guitar Pick that you will receive, there is a high level of variety in our picks due to the nature of many of our natural materials.