It's the best of both worlds. A light and stiff direct mount chainring with accurate Quarq power measurement elegantly hidden inside the DUB spindle lets you stealthily gather the data you need to progress. So you can focus your attention on the stunning finish of the carbon fiber crank arm. FEATURES - DUB-PWR spindle-based unit measures left side power to calculate total watts - Long battery life (400+ hours) to power a season of rides - User replaceable AAA lithium battery - DUB bottom bracket adds durability and simplicity - Waterproof (IPX7 waterproof to 1 meter for 30 minutes) - Lightweight (less than 40g heavier than standard crankset) - Compatible with 135mm and 142mm rear spacing