2 pcs Mono 100W Transistor power amplifier Bare PCB DIY circuit board &lt;==Beware to Add To Cart !!! Only sold by Thaikits for product warrantee and free technical support. This circuit uses IC to be pre-driver and transistor at output stage power transistor 2N3055 / MJ2955 It requires dual power supply +34V and -34V / It comes with the schematic diagram !!! PCB size = 7.5cm x 10.4cm