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. The Protege works for 1/8-1/2 size Violins.