The downhill specific saint m820825 stages power replaces non drive crank arm on existing shimano saint m820825 model cranks the stages power meter fits all saint cranksets riders need only to select crank arm lengthspecifications accuracy 2 weight only adds 20gr to base crank arm battery life 200 hours coin cell cr2032 power range watts 0 2500 cadence range rpm 20 220 frame compatibility most frames see fit guide in our support section crank compatibility shimano sai