Overview Product Description BU931P.pdf High voltage ignition coil driver. Product Videos Custom Field Product Reviews Write a Review Write a Review × ST BU931P ; Transistor NPN-Darlington 400V 15A 135W MHz, TO-218 Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Email * Review Subject * Comments *