Wedge grips apply a self-loading clamping mechanism that allows holding samples at high forces. They are often used to test metal and composite specimens and other materials exhibiting high breaking strengths. Wedge grips are the recommended grip type in tests such as ASTM E8 Metals Tensile Testing, ASTM E517 Sheet Metal Plastic Strain Ratio Testing, and ASTM D3039 Polymer Matrix Composite Tensile Testing.