Machine cut from aluminum pipe stock that is 7mm thick. Two main gears, two pinion gears, four ball bearings, and the main shaft are all made of stainless steel. The graphite drag washer's performance is unaffected by water and is designed to withstand 30 miles of line being pulled off of it before performance is noticeably affected. To top it off, Tiagra features a two-speed gearing system that shifts instantly (even while cranking) because it consists of two complete sets of pinion and drive gears that are both constantly engaged.