A process for preparing polyether alcohols by addition of alkylene oxides onto H-functional starter substances in the presence of multimetal cyanide catalysts, wherein the multimetal cyanide catalysts are microporous and have a specific surface area of more than 100 m2g, determined by nitrogen adsorption at 77 K. The first gate is disposed laterally from the body and the second gate is disposed laterally from the first gate. In the arrangement where the anode and the attachment are in the same hole, the pin passes into or through the anode so as to hold the anode rigidly within the hole. The active electrode may be moved relative to the tendon during, or after, the application of electrical energy to damage or sculpt a void within the tendon, such as a hole, channel, crater, or the like.