Avio PowerSense Pro Left Crank Arm Power Meter - BlackAvio PowerSense Pro Left Crank Arm Power Meter Black Select Length: Made with aircraft grade H15 aluminium, it is hard case anodised for added durability. The Avio PowerSense Pro crank works with all head unitsoperating ANT+. This Direct Hollowtech II Shimano crank, has high compatibility with Hollowtech II bikes, and has arm drop in replacement. Each Avio PowerSense is individually calibrated before preparation of delivery to ensure a + 2% accuracy