The 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.Key Features:Spindle-based unit measures left side power to calculate total wattsLong battery life (400+ hours) to power a season of ridesUser replaceable AAA lithium batteryDUB bottom bracket adds durability and simplicityWaterproof (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 controlXPLR chainline for compatibility with Full Mount rear derailleurs