Set of 6 grade 8.8, zinc plated steel, M6 bolts, wave washers and flat washers. Use to install the Opel GT aluminum valve cover ONLY. These bolts are too long for use with the standard stamped steel valve covers that require special bolts with wing shaped washers. Recommended to tighten until the wave washer flatens out. This is to avoid over tightening that damages the cork valve cover gasket. Recommended torque of 2.5 lbft.