104BCD and Square Tapered Hole: 104mm BCD is popular crankset, but please make sure your MTB bike bottom bracket is square tapered interface type.
Multi Speed Support: the crankset can use as 1x, or 2x and 3x speed. Use it as 1x speed is more popular. It comes with 1 unit 104bcd narrow wide chainring in package, works for 7-12s chain. Crankset hole for pedal is 9/16 inch(14mm).
Forged Aluminum and CNC: it is 3D forged and CNC processing. Material Aluminum 6061. Hollow tech applied for lightweight. A pair crankset weight 590g only.
170mm and 175mm for Choose: length refers to hole center to hole center distance. Usually buy 170mm is fine. 175mm model is 5mm longer.