Crank arm is new take off and installed stages power meter in it's place.
Crank arm length 170mm
Model FC-6800
You will need the small Shimano Safety Plate that goes between the screws. Lost that somehow. You should have one on current crank arm or buy for $8
https://www.amazon.com/SHIMANO-Hollowtech-Crank-Arm-Safety/dp/B003RLNCS6
Meet outside my building in Midtown. Yes it is available. Thanks.