Lighter and smoother, the Shimano SLX FC-M7130 Super Boost 12V cranks adopt a DirectMount design for ease of use and switch to 12-speed transmission. This model is composed of a rigid aluminium base for a very good power transfer. It is equipped with the famous Hollowtech II hollow crank system offering an integrated crankshaft with high resistance to wear for a high quality of rotation over time. Hollowtech II technologyPerfect balance between stiffness, stability, weight and rotational efficiency. The concept of Hollowtech II technology was designed to produce an optimised crankset that minimises the amount of effort the rider has to put into the drivetrain. The high stiffness of the crankset ensures the efficiency of power transmission when pedalling, while its low weight takes the strain off the rider, especially on longer journeys. The crankset was developed with an optimal ratio between stiffness and low weight in mind. Hollowtech technology allows for extremely light, hollow crank arms that are manufactured using Shimano's exclusive forging technology for maximum stiffness. In addition, the Hollowtech II crankset has the right crank firmly connected to the axle of the bottom bracket, achieving an optimal balance between maximum stiffness and minimum weight. The externally mounted bottom bracket offers better weight distribution and more stability, which ensures more efficient power transmission. When developing the Hollowtech II crankset, emphasis was placed on achieving an optimal balance between stiffness and rotational efficiency as well as low weight and an attractive appearance. The Hollowtech II crankset also features high-quality precision seals in the bearing area to extend durability and maintain the excellent rotational efficiency in the long term.