Product details:

Stages Cycling G3 Power L Shimano GRX R8100 Power Meter The Stages Cycling G3 Power L Shimano GRX R8100 Power Meter allows accurate off-road power measurement to aid training and racing. The unit adds just 15 grams to the weight of the base GRX crank arm and is accurate to +/- 1.5%, with the capacity to measure up to 2,500 watts. Automatic temperature compensation ensures that the data is accurate even in changeable conditions. The power meter has a 200+ hours battery life and the CR2032 battery can be easily replaced without recourse to any tools whilst firmware upgrades are performed wirelessly.