Fits 1/2 to full size violins and 12-15 violas. The “PSR Extra” violin viola shoulder rest is designed for the performer that has more space to fill between the shoulder and the neck. Uniquely designed, so that the thicker side of the shoulder pad is over the back of the shoulder instead of the front. One “PSR Elastic Band” and one “PSR Magic Strip” are currently included. Try the “STRAIGHT” or “ANGLED” placements for your preferred comfort, made of resilient contoured ergonomically designed foam with great memory to bounce back to its original shape. Our PATENT NUMBER 7,262,352 design curve assists proper placement for your shoulder rest.