Part Number Breakdown:

Example: PS10BMG172S31

PS = Pole Star shaded pole motor, 10 = Power (watts), B = Bearing Type (B = Ball / S = Sleeve) , M = Mono is single Shaft,  G = G = Grid / R = ring mounting, 172 = Size of Blade (mm), S = Airflow Direction (S = sucking or B = blowing), 31 = Degree of the blade.