Bonmusica Viola Shoulder RestBonMusica Viola Shoulder Rests are a popular choice for viola players wanting a well fitting shoulder rest. Your shoulder rest will come with detailed instructions. This rest can also be used by left handed players. Materials: Plastic coated aluminum with foam rubber padding to support the side facing the body. Natural rubber cover for the holding claws to prevent sound leakage and damage to the instrument. Nylon fasteners for weight reduction.