Quarq

SRAM Quarq S975 CinQo Power Meter Crankset: 172.5mm x 53/39t Double- Carbon - GPX (EXC+)

Highly rated and originally very pricey powermeter crank.  It features SRAM's integrated carbon crank arms, SRAM RED chainrings, and a spider based powermeter.  Tool-less coin battery...

Quarq Elsa 10R SRAM Red Power Meter Crankset: 170mm x 50/34t Compact - Carbon - GPX (Near Mint+ Low Miles)

Highly rated and originally very pricey powermeter crank.  It is a rebadged SRAM RED GPX Exogram crank and chainrings, with the Elsa powermeter integrated from the factory.  Tool-less...