inserted into the power getting receptacle the silicone ring 26 will be inserted into a gap between an outer wall of the plug and inner wall of the receptacle thus preventing loosing of the plug the indicating component 1 and power getting plug 2 are connected to each other by a pivoting construction as shown in fig5 in details a pair of first pivoting portions 221 is formed at one side of an exposed end surface of the power getting plug of the lower cover 22 the pair of the pivoting portions takes form of a pair of ear portions each has a horizontal through hole defined therein as shown in fig5 a groove 2211 is defined between the two ear portions correspondingly a pair of second pivoting portions 1121 is formed on the base 112 at the same side adjacent the bottom surface of the base or they may be directly formed on the bottom surface the pair of second pivoting portions 1121 engages the first pivoting portions 221 that is an ear portion with a horizontal through hole is formed as shown in fig5 this ear portion may be inserted into the groove 2211 and be located coaxially with the through holes of the first.