Power2max
Mounts directly to crankset, then mount a chainring to it. Gives left and right crank power readings. Uses a simple coin type (CR2032?) battery. I’m not training anymore so I no longer use this tool.
ANT+ and Bluetooth communications
I had it on a SRAM drivetrain.
I have a variety of chainrings that can be selected to fit your setup sized from 32t to 46t. It came with a 40t Praxxis.