The M30 is part of their 30mm spindle line of cranks which also includes the A30, R30 and G30 models. The “M” stands for mountain and the “30” is for the 30mm spindle. The best way to describe this model is, “It’s a mountain bike crank”. Simple. Check out the table here and compare the specs of all four crank combinations to help decide which model would best suit your needs.
Note: Spindle, crank bolts, extractors, adjusting collar, and chairing lockring included. Chainrings and bottom bracket sold separately.