AC Delco DuraStop® Brake Pads Deliver Ultimate Stopping Power! DuraStop brakes were one of the first aftermarket lines to be tested and validated by Dual Dynamometer Differential Effectiveness Analysis (D3EA). The D3EA process, conducted by an independent testing laboratory, lets you know that ACDelco DuraStop replacement brake pads successfully meet all federal safety standards set for new vehicles. Just look for the D3EA seal on DuraStop packaging.