Mach One Plastic Violin Shoulder Rest Plastic, 4/4-3/4 This may be the best shoulder rest design ever! Ergonomically designed to be one of the most comfortable rests on the market today The feet are molded out of 100% nylon so there is no risk of scratching your instrument Try one today, you will be amazed at the difference The Mach one is fully adjustable for width and height The "S" shape fits comfortably on your shoulder and minimizes the size of the feet