There's no better way to enhance your training and racing performance than by training with power. Lucky for you, we've developed a Quarq-based power meter for S-Works road cranksets that'll help get you to the next level.   It utilizes an advanced digital strain gauge matrix system that's calibrated to an alarming +/- 0.5% accuracy, which is around 1.5% more precise than its comparable competition. And on the subject of competition, the SpeedZone ANT+ Power Spider is easier to self-maintain and calibrate, so you don't have to send the whole unit back in order to swap out the batteries. The whole unit, with an S-Works crankset, typically tips the scales at less than 720 grams (depending on crank length and tooth choice at the chainrings), which is less than a 50-gram addition. It also pairs with your Garmin, SRM, and Suunto devices via ANT+, and the CR2032 batteries have a typical runtime of over 300 hours.