This Mac One Viola shoulder-rest is hand carved from beautiful, natural maple wood. The Mach one shoulder-rests are ergonomically designed to be one of the most comfortable rests on the market. The “S” shape fits comfortably on your shoulder and minimizes the size of the feet, which are molded out of 100% nylon so there is no risk of scratching your instrument. These are molded from a single piece of maple and have a lifetime guarantee.