The QXL rings are the latest product from Rotor, with increased ovalization over the standard Q-Rings -- 16% ovalized vs. 10% with regular Q-Rings. Rotor intends this design not to replace standard Q-Rings, but rather to complement them. Each is optimized for different rider profiles and situations. Standard Q rings aim to boost performance by varying the resistance in the pedal stroke. QXL rings claim to be more suited to higher output riders. I have ridden them all day at lower power levels and would be comfortable recommending them for riders new to oval cranks.