This 27mm wrench (AKA thin wrench), is a step beyond Porsche's wrench. It is needed to adjust the cam & balance belt tension. It is made using water-jet technology and of cold rolled steel. It has a black oxide coating and features a 6 inch handle with a thin, yet oversized, head. The thin part is needed to get under the roller's off-center pivot nut and the oversized diameter makes the wrench strong and helps to prevent the belt from riding up on the wrench edge. It also has a unique bent offset needed to reach the cam belt offset roller. Note: compare my price for this tool to Porsche's price of $56.00; also if you're considering this wrench from other vendors, look closely at their pictures, some are cheap imported stampings, re-cut bicycle wrenches or even farm equipment service wrenches. They are not nearly as strong and/or do not have a correctly bent handle to reach the cam belt's offset roller.
One side note here... Some of the early model 944s were equipped with a "small nut rollers." Porsche dealers replaced these as part of the efforts to reduce the number of cam belt failures. And, for the most part, these early rollers have disappeared. Occasionally one of the old rollers will surface though. If you order new rollers, settle only for the later style, 27 mm rollers. The 27mm thin wrench will not fit the smaller rollers. More info on 24mm vs 27 mm rollers available here.
