M13/40 of the 1st series had long but thinn fenders with open oval holes (WT doesn't shows it correctly), no radio, manual turret drive and loading system, 2 spare road wheels at the back and jack on front fender, early 'box' shaped radiator cover, longitudinal grills and flat turret roof.
M13/40 of the 2nd series had short but thicker fenders with open oval holes, recived a radio, electric turret drive and semi-automatic gun reloading system, only 1 spare road wheel and jack moved to the place of previous second wheel at the back, still same early radiator cover, longitudinal grills and flat turret roof. Max. depression of the gun was reduced from -15° to -10° due to new loading system.
M13/40 of the 3rd series had only few differences from previous series and they were: new 'mushroom' shaped radiator cover, little "box" at the turret roof to increase max. gun depression again to - 15° and smoother mufflers.
M14/41 returned to long fenders (first 50 tanks still had short ones) but this time they were additionally reinforced, recived new engine that changed grills to transversal ones, oval holes on fenders were hidden under little plates and at the end of production recived mud clearing blades behind sprockets and new 47/40 gun. WT shows jack position incorrectly, it should remain at the back of the hull.
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