We cut grams out of our aluminum crankarms, but didn't cut corners on power measurement. Our light and accurate spindle-based power unit nestles into our striking redesigned arms to give you the data you need, and our newest direct mount chainrings are light and stiff while looking good. Features - 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 mins) - Lightweight (less than 40g heavier than standard crankset) - SRAM X-SYNC wide-tooth, narrow-tooth chainring technology provides maximum chain control - Wide chainline for compatibility with Full Mount rear derailleurs