The AcoustaGrip Protege protects against bruising, sores and marks on the chin, neck and collarbone and relieves shoulder pain. The Protege Youth Size Shoulder Rests offer 3 unique layers of acoustical material, each of a different density and responsiveness. One layer is made from a special acoustical material, delivering enhanced sound, ultimate comfort and a secure hold. Another layer attaches simply with air to the back of your instrument using micro-air technology. The third layer gives this Protege model added projection, increased resonance and allows the musician to create the maximum overtones for the Violin or Viola. The Protege works for 1/8-1/2 size Violins.