XX crank arm with a subtly integrated power meter to record and deliver live, accurate power readings to your head unit- Spider design uses a proprietary chainring mount system which allows reduced weight without compromising reliability- Dual sided power measurement system calculates total watts - it's subtle, lightweight, and boasts an extra long battery life- Compatible with the Flight Attendant system, allowing for total connectivity between all AXS enabled component- BB and BB DUB spacers are not included- 174mm Q-Factor