The new Miche Attiva Chainset is a collaboration between Miche and SRM to create an "affordable" chainset. The Attiva chainset has been designed around the SRM power meter and the integrity of your training data has long been SRM's life's work. The power meter measures the force coming from the legs of a rider with strain gauges mounted inside the spider of the crank set. The spider design allows for a stiff measuring platform, translating to stable and consistent data. Accuracy is meaningless if the measuring device isn't durable enough for the environment in which it will be used. The SRM Spider design is engineered to be completely sealed from outside elements such as rain, snow, mud, sand, and event bike washes with harsh degreasers! Compatible with 9, 10, or 11 speed for Road or Triathlon. Unlike other chainsets that are adapted to be compatible with SRM, the Attiva doesn't require you to recalibrate the power meter when upgrading or changing your chainring ratio. This means that you can be free to change your gear ratio on the fly, without having to worry about setting up your power meter.