a plurality of connectors, wherein each of the connectors comprises a terminal part formed in one side of the PCB and provided with a terminal hole, and a connector pin comprising an insertion part formed vertically so as to be inserted into the terminal hole, and a contact part protruding and extending from the insertion part, the contact part being bent several times so as to be deformed elastically, the contact part having a bottom surface formed levelly so as to be contacted with an upper surface of the terminal part and a top surface electrically connected to a pad part provided in a target PCB for connection; and

a plurality of assembly holes and screw members to connect the PCB to a target PCB.