With Garmin's Vector S you'll find yourself breaking through mental barriers and eking out those last few watts. The Vector S offers precise power measurement of your left leg and uses that information to approximate your total and average power. All of this comes in a rugged, ultra-convenient, discreet package that's integrated with a Look Keo Pedal. Garmin encased the sensitive strain gauge inside the stainless steel pedal spindle for years of durability and accuracy to within +/- 2%. The pedal bodies are built of tough, light carbon, while the battery/ANT+ pod hangs protected beneath the left crank arm. Switching the pedals and pod between bikes is blissfully hassle-free and takes less time than getting kitted up. Garmin also offers you the ability to upgrade to the dual-sensing Vector system which provides additional data about the power produced by each leg.