Sankyo AX040056A, MSCS048A08 Stepper Motor T31251 by Sankyo for Richo industrial quality. uni polar 5 wire design 2 x pr of windings + common ( can be easily converted to other modes) dims: motor: 22mm deep x 42mm diameter (excluding flange - 57mm max with two M2.5 threadwed holes at approx 49mm centres) This motor is fine for small robotoc projects or CNC type positioning projects, not big enough for a router / engraver but fine for a laser cutter / pen plotter great for DIY rep-Rap machine. includes 17 tooth brass cog ( easily removed) 3mm spindle retail new $76-95 Ouch ! status: bought for a mothballed laser cutter project, fitted for a week, used for about 5 hours to test driver circuitry, so not new... hence massive price reduction.