The surface of the extending portion 22 of each of the plurality of the conductive terminals 20 adjacent to and projecting beyond a front surface of the at least one sealing board 43 is coated with the layer of the insulation ink by the pad printing technology to form the insulation layer 24. A length of the insulation layer 24 of the extending portion 22 of each of the plurality of the conductive terminals 20 projecting beyond the front surface of the at least one sealing board 43 is approximately 0.25 mm. The insulation layer 24 of the extending portion 22 of each of the plurality of the conductive terminals 20 is exposed to the at least one docking surface 101, and is adjacent to and projects beyond the front surface of the at least one sealing board 43. A surface of the front end of the extending portion 22 of each of the plurality of the conductive terminals 20 exposed out of the insulating housing 10, and adjacent to and projecting beyond the front surface of the at least one sealing board 43 is coated with the layer of the insulation ink by the pad printing technology to form the insulation layer 24. A surface of a rear end of the extending portion 22 of each of the plurality of the conductive terminals 20 adjacent to the front surface of the at least one sealing board 43 is capable of being coated with the layer of the insulation ink by the pad printing technology to form the insulation layer 24 and being received in one of the terminal grooves 124 of the insulating housing 10.