The Power Torque crank assembly was designed to reduce costs while maintaining performance to bring the crankset in at a reasonable price, with little to no decrease in performance. The next-level Ultra Torque system is very expensive top produce and Campy's engineers were looking for a less expensive alternative that gives the rider similar performance. This is actually true of most Centaur components: bring the rider similar performance of the upper end groups with emphasis on value.
Power Torque cranks feature a full length spindle fixed into the right crank arm. The splined left arm slides on to the splined spindle and is held in place with a 14mm hex (Allen) bolt. The right side sealed bearing is attached to the crank and the left side is installed in the Power Torque BB cup. The Power Torque system (not compatible with Ultra Torque) requires Power Torque bottom bracket cups available separately.
As far as the crankset itself, the arms and spider are constructed from full carbon unidirectional/multidirectional spider and arms. The chainrings go under heavy machining with 8 different shift zones, MPS - Micro Precision Shifting chainrings (these are the shifting ramps) and AFT - anti friction coating.
All-in-all, these are a beautiful set of cranks that Campy has clearly put a lot of time and thought into. The Power Torque system works well and the quality of the component is pure Campagnolo.