Feedback Sports Digital Chain Gauge
$80 / feedbacksports.com
What's the best way to destroy your Gucci-expensive crankset and cassette? Keep running your worn-out chain. Is it time to change your chain? Feedback Sports' new gauge makes answering that question dead simple: If the digital display reads 0.8 millimeters or more, it's time to rip that sucker off your bike and transform it into a thoughtful Mother's Day gift.